Got a reproduce for this error when working on crbug.com/893161

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5cd8c123e452c0b76fbbcaf53e82d86ca7d54930

commit 5cd8c123e452c0b76fbbcaf53e82d86ca7d54930
Author: Luciano Pacheco <lucmult@chromium.org>
Date: Fri Oct 12 00:07:24 2018

Files app: Select My files when there are no volumes

Make Files app select "My files" when there are no available volumes,
this to allow Files app to behave properly when volumes subsequently
become available.

Change DirectoryModel.onVolumeInfoListUpdated_ method to check for
non-null |displayRoot| before trying to change to |displayRoot|. This
fixes the error "Cannot read property 'getParent' of null" when Drive
volume becomes available before Downloads volume, which is the default
volume/root.

Change FakeDriveFs to unbind the two mojo bindings if they're bound, so
DriveFsTestVolume can re-mount itself.

Test: browser_tests --gtest_filter="*/fileDisplayWithoutVolumesThenMount*"
Bug: 893161,  884967 
Change-Id: Ic813b25261530495c11c9f641a92f6e07f883702
Reviewed-on: https://chromium-review.googlesource.com/c/1272418
Reviewed-by: Noel Gordon <noel@chromium.org>
Reviewed-by: Sam McNally <sammc@chromium.org>
Commit-Queue: Luciano Pacheco <lucmult@chromium.org>
Cr-Commit-Position: refs/heads/master@{#599026}
[modify] https://crrev.com/5cd8c123e452c0b76fbbcaf53e82d86ca7d54930/chrome/browser/chromeos/file_manager/file_manager_browsertest.cc
[modify] https://crrev.com/5cd8c123e452c0b76fbbcaf53e82d86ca7d54930/chrome/browser/chromeos/file_manager/file_manager_browsertest_base.cc
[modify] https://crrev.com/5cd8c123e452c0b76fbbcaf53e82d86ca7d54930/chromeos/components/drivefs/fake_drivefs.cc
[modify] https://crrev.com/5cd8c123e452c0b76fbbcaf53e82d86ca7d54930/ui/file_manager/file_manager/foreground/js/directory_model.js
[modify] https://crrev.com/5cd8c123e452c0b76fbbcaf53e82d86ca7d54930/ui/file_manager/file_manager/foreground/js/file_manager.js
[modify] https://crrev.com/5cd8c123e452c0b76fbbcaf53e82d86ca7d54930/ui/file_manager/integration_tests/file_manager/file_display.js

It's fixed with the patch above.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/402571f89e1aff1627ccf491110764c74029e3de

commit 402571f89e1aff1627ccf491110764c74029e3de
Author: Findit <findit-for-me@appspot.gserviceaccount.com>
Date: Fri Oct 12 13:17:58 2018

Revert "Files app: Select My files when there are no volumes"

This reverts commit 5cd8c123e452c0b76fbbcaf53e82d86ca7d54930.

Reason for revert:

Findit (https://goo.gl/kROfz5) identified CL at revision 599026 as the
culprit for flakes in the build cycles as shown on:
https://findit-for-me.appspot.com/waterfall/flake/flake-culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyQwsSDEZsYWtlQ3VscHJpdCIxY2hyb21pdW0vNWNkOGMxMjNlNDUyYzBiNzZmYmJjYWY1M2U4MmQ4NmNhN2Q1NDkzMAw

Sample Failed Build: https://ci.chromium.org/buildbot/chromium.memory/Linux%20ChromiumOS%20MSan%20Tests/9016

Sample Failed Step: viz_browser_tests

Sample Flaky Test: FileDisplay/FilesAppBrowserTest.Test/fileDisplayWithoutVolumesThenMountDrive_DriveFs

Original change's description:
> Files app: Select My files when there are no volumes
> 
> Make Files app select "My files" when there are no available volumes,
> this to allow Files app to behave properly when volumes subsequently
> become available.
> 
> Change DirectoryModel.onVolumeInfoListUpdated_ method to check for
> non-null |displayRoot| before trying to change to |displayRoot|. This
> fixes the error "Cannot read property 'getParent' of null" when Drive
> volume becomes available before Downloads volume, which is the default
> volume/root.
> 
> Change FakeDriveFs to unbind the two mojo bindings if they're bound, so
> DriveFsTestVolume can re-mount itself.
> 
> Test: browser_tests --gtest_filter="*/fileDisplayWithoutVolumesThenMount*"
> Bug: 893161,  884967 
> Change-Id: Ic813b25261530495c11c9f641a92f6e07f883702
> Reviewed-on: https://chromium-review.googlesource.com/c/1272418
> Reviewed-by: Noel Gordon <noel@chromium.org>
> Reviewed-by: Sam McNally <sammc@chromium.org>
> Commit-Queue: Luciano Pacheco <lucmult@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#599026}

Change-Id: I883485c8fc1bdcc22dba93cc4b03b7c157dcb5f2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 893161,  884967 ,  889703 
Reviewed-on: https://chromium-review.googlesource.com/c/1278063
Cr-Commit-Position: refs/heads/master@{#599190}
[modify] https://crrev.com/402571f89e1aff1627ccf491110764c74029e3de/chrome/browser/chromeos/file_manager/file_manager_browsertest.cc
[modify] https://crrev.com/402571f89e1aff1627ccf491110764c74029e3de/chrome/browser/chromeos/file_manager/file_manager_browsertest_base.cc
[modify] https://crrev.com/402571f89e1aff1627ccf491110764c74029e3de/chromeos/components/drivefs/fake_drivefs.cc
[modify] https://crrev.com/402571f89e1aff1627ccf491110764c74029e3de/ui/file_manager/file_manager/foreground/js/directory_model.js
[modify] https://crrev.com/402571f89e1aff1627ccf491110764c74029e3de/ui/file_manager/file_manager/foreground/js/file_manager.js
[modify] https://crrev.com/402571f89e1aff1627ccf491110764c74029e3de/ui/file_manager/integration_tests/file_manager/file_display.js

I'm working on de-flaking this test.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/6f65bd26330cf709e4a4c4eb60876de5849f94d5

commit 6f65bd26330cf709e4a4c4eb60876de5849f94d5
Author: Luciano Pacheco <lucmult@chromium.org>
Date: Wed Oct 17 05:10:44 2018

Files app: Select My files when there are no volumes

Make Files app select "My files" when there are no available volumes,
this to allow Files app to behave properly when volumes subsequently
become available.

Change DirectoryModel.onVolumeInfoListUpdated_ method to check for
non-null |displayRoot| before trying to change to |displayRoot|. This
fixes the error "Cannot read property 'getParent' of null" when Drive
volume becomes available before the (default) Downloads volume/root.

Change FakeDriveFs to unbind the two mojo bindings if they're bound, so
DriveFsTestVolume can re-mount itself.

Changes since revert:
1. Add a new function |getVolumesCount| to return the number of volumes
available in the background page.
2. Add the new function above to wait for background page to have all
volumes before un-mounting and wait it to unmount all volumes.
3. Change some logs from error to warn because errors are expected and
handled when initializing volumes that are unmounting/unmounted in the
backend.
4. Change selector used to click on Drive to actually wait for
"My Drive" to be available.
5. A bit of more info in some logs around volume initialization.

Test: browser_tests --gtest_filter="*/fileDisplayWithoutVolumesThenMount*"
Bug: 893161,  884967 ,  894799 
Change-Id: I7dcb340991750e9e79a9963990b614c6d7275890
Reviewed-on: https://chromium-review.googlesource.com/c/1278619
Reviewed-by: Noel Gordon <noel@chromium.org>
Reviewed-by: Sam McNally <sammc@chromium.org>
Commit-Queue: Luciano Pacheco <lucmult@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600282}
[modify] https://crrev.com/6f65bd26330cf709e4a4c4eb60876de5849f94d5/chrome/browser/chromeos/file_manager/file_manager_browsertest.cc
[modify] https://crrev.com/6f65bd26330cf709e4a4c4eb60876de5849f94d5/chrome/browser/chromeos/file_manager/file_manager_browsertest_base.cc
[modify] https://crrev.com/6f65bd26330cf709e4a4c4eb60876de5849f94d5/chromeos/components/drivefs/fake_drivefs.cc
[modify] https://crrev.com/6f65bd26330cf709e4a4c4eb60876de5849f94d5/ui/file_manager/file_manager/background/js/test_util_base.js
[modify] https://crrev.com/6f65bd26330cf709e4a4c4eb60876de5849f94d5/ui/file_manager/file_manager/background/js/volume_manager_impl.js
[modify] https://crrev.com/6f65bd26330cf709e4a4c4eb60876de5849f94d5/ui/file_manager/file_manager/background/js/volume_manager_util.js
[modify] https://crrev.com/6f65bd26330cf709e4a4c4eb60876de5849f94d5/ui/file_manager/file_manager/foreground/js/directory_model.js
[modify] https://crrev.com/6f65bd26330cf709e4a4c4eb60876de5849f94d5/ui/file_manager/file_manager/foreground/js/file_manager.js
[modify] https://crrev.com/6f65bd26330cf709e4a4c4eb60876de5849f94d5/ui/file_manager/integration_tests/file_manager/file_display.js

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/103069350367d5c2cf85897e99e899b77a82f6b8

commit 103069350367d5c2cf85897e99e899b77a82f6b8
Author: Christos Froussios <cfroussios@chromium.org>
Date: Wed Oct 17 13:55:27 2018

Revert "Files app: Select My files when there are no volumes"

This reverts commit 6f65bd26330cf709e4a4c4eb60876de5849f94d5.

Reason for revert: Speculative revert
Suspected of breaking browser_tests, ebui_polymer2_browser_tests, single_process_mash_browser_tests and viz_browser_tests
on Linux ChromiumOS MSan

Note: resolved conflicts with ES6 refactoring, therefore running tests...

Bug:  896219 

Original change's description:
> Files app: Select My files when there are no volumes
>
> Make Files app select "My files" when there are no available volumes,
> this to allow Files app to behave properly when volumes subsequently
> become available.
>
> Change DirectoryModel.onVolumeInfoListUpdated_ method to check for
> non-null |displayRoot| before trying to change to |displayRoot|. This
> fixes the error "Cannot read property 'getParent' of null" when Drive
> volume becomes available before the (default) Downloads volume/root.
>
> Change FakeDriveFs to unbind the two mojo bindings if they're bound, so
> DriveFsTestVolume can re-mount itself.
>
> Changes since revert:
> 1. Add a new function |getVolumesCount| to return the number of volumes
> available in the background page.
> 2. Add the new function above to wait for background page to have all
> volumes before un-mounting and wait it to unmount all volumes.
> 3. Change some logs from error to warn because errors are expected and
> handled when initializing volumes that are unmounting/unmounted in the
> backend.
> 4. Change selector used to click on Drive to actually wait for
> "My Drive" to be available.
> 5. A bit of more info in some logs around volume initialization.
>
> Test: browser_tests --gtest_filter="*/fileDisplayWithoutVolumesThenMount*"
> Bug: 893161,  884967 ,  894799 
> Change-Id: I7dcb340991750e9e79a9963990b614c6d7275890
> Reviewed-on: https://chromium-review.googlesource.com/c/1278619
> Reviewed-by: Noel Gordon <noel@chromium.org>
> Reviewed-by: Sam McNally <sammc@chromium.org>
> Commit-Queue: Luciano Pacheco <lucmult@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#600282}

TBR=noel@chromium.org,sammc@chromium.org,lucmult@chromium.org

Change-Id: Ifaadea8b49cffc6deb70b429a42bab39d4a3d52b
Bug: 893161,  884967 ,  894799 
Reviewed-on: https://chromium-review.googlesource.com/c/1286146
Commit-Queue: Christos Froussios <cfroussios@chromium.org>
Reviewed-by: Christos Froussios <cfroussios@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600376}
[modify] https://crrev.com/103069350367d5c2cf85897e99e899b77a82f6b8/chrome/browser/chromeos/file_manager/file_manager_browsertest.cc
[modify] https://crrev.com/103069350367d5c2cf85897e99e899b77a82f6b8/chrome/browser/chromeos/file_manager/file_manager_browsertest_base.cc
[modify] https://crrev.com/103069350367d5c2cf85897e99e899b77a82f6b8/chromeos/components/drivefs/fake_drivefs.cc
[modify] https://crrev.com/103069350367d5c2cf85897e99e899b77a82f6b8/ui/file_manager/file_manager/background/js/test_util_base.js
[modify] https://crrev.com/103069350367d5c2cf85897e99e899b77a82f6b8/ui/file_manager/file_manager/background/js/volume_manager_impl.js
[modify] https://crrev.com/103069350367d5c2cf85897e99e899b77a82f6b8/ui/file_manager/file_manager/background/js/volume_manager_util.js
[modify] https://crrev.com/103069350367d5c2cf85897e99e899b77a82f6b8/ui/file_manager/file_manager/foreground/js/directory_model.js
[modify] https://crrev.com/103069350367d5c2cf85897e99e899b77a82f6b8/ui/file_manager/file_manager/foreground/js/file_manager.js
[modify] https://crrev.com/103069350367d5c2cf85897e99e899b77a82f6b8/ui/file_manager/integration_tests/file_manager/file_display.js

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/033dff086bc81067ff0a4f5dff54434b5293aa9a

commit 033dff086bc81067ff0a4f5dff54434b5293aa9a
Author: Christos Froussios <cfroussios@chromium.org>
Date: Wed Oct 17 16:52:42 2018

Reland "Files app: Select My files when there are no volumes"

This reverts commit 103069350367d5c2cf85897e99e899b77a82f6b8.

Reason for revert: Undoing speculative revert
The CL was not the culprit

Original change's description:
> Revert "Files app: Select My files when there are no volumes"
> 
> This reverts commit 6f65bd26330cf709e4a4c4eb60876de5849f94d5.
> 
> Reason for revert: Speculative revert
> Suspected of breaking browser_tests, ebui_polymer2_browser_tests, single_process_mash_browser_tests and viz_browser_tests
> on Linux ChromiumOS MSan
> 
> Note: resolved conflicts with ES6 refactoring, therefore running tests...
> 
> Bug:  896219 
> 
> Original change's description:
> > Files app: Select My files when there are no volumes
> >
> > Make Files app select "My files" when there are no available volumes,
> > this to allow Files app to behave properly when volumes subsequently
> > become available.
> >
> > Change DirectoryModel.onVolumeInfoListUpdated_ method to check for
> > non-null |displayRoot| before trying to change to |displayRoot|. This
> > fixes the error "Cannot read property 'getParent' of null" when Drive
> > volume becomes available before the (default) Downloads volume/root.
> >
> > Change FakeDriveFs to unbind the two mojo bindings if they're bound, so
> > DriveFsTestVolume can re-mount itself.
> >
> > Changes since revert:
> > 1. Add a new function |getVolumesCount| to return the number of volumes
> > available in the background page.
> > 2. Add the new function above to wait for background page to have all
> > volumes before un-mounting and wait it to unmount all volumes.
> > 3. Change some logs from error to warn because errors are expected and
> > handled when initializing volumes that are unmounting/unmounted in the
> > backend.
> > 4. Change selector used to click on Drive to actually wait for
> > "My Drive" to be available.
> > 5. A bit of more info in some logs around volume initialization.
> >
> > Test: browser_tests --gtest_filter="*/fileDisplayWithoutVolumesThenMount*"
> > Bug: 893161,  884967 ,  894799 
> > Change-Id: I7dcb340991750e9e79a9963990b614c6d7275890
> > Reviewed-on: https://chromium-review.googlesource.com/c/1278619
> > Reviewed-by: Noel Gordon <noel@chromium.org>
> > Reviewed-by: Sam McNally <sammc@chromium.org>
> > Commit-Queue: Luciano Pacheco <lucmult@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#600282}
> 
> TBR=noel@chromium.org,sammc@chromium.org,lucmult@chromium.org
> 
> Change-Id: Ifaadea8b49cffc6deb70b429a42bab39d4a3d52b
> Bug: 893161,  884967 ,  894799 
> Reviewed-on: https://chromium-review.googlesource.com/c/1286146
> Commit-Queue: Christos Froussios <cfroussios@chromium.org>
> Reviewed-by: Christos Froussios <cfroussios@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#600376}

TBR=noel@chromium.org,sammc@chromium.org,cfroussios@chromium.org,lucmult@chromium.org

Change-Id: I388a94fe12c7d40ac7ea779353c3b220bd5b5952
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug:  896219 , 893161,  884967 ,  894799 
Reviewed-on: https://chromium-review.googlesource.com/c/1286853
Reviewed-by: Christos Froussios <cfroussios@chromium.org>
Commit-Queue: Christos Froussios <cfroussios@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600429}
[modify] https://crrev.com/033dff086bc81067ff0a4f5dff54434b5293aa9a/chrome/browser/chromeos/file_manager/file_manager_browsertest.cc
[modify] https://crrev.com/033dff086bc81067ff0a4f5dff54434b5293aa9a/chrome/browser/chromeos/file_manager/file_manager_browsertest_base.cc
[modify] https://crrev.com/033dff086bc81067ff0a4f5dff54434b5293aa9a/chromeos/components/drivefs/fake_drivefs.cc
[modify] https://crrev.com/033dff086bc81067ff0a4f5dff54434b5293aa9a/ui/file_manager/file_manager/background/js/test_util_base.js
[modify] https://crrev.com/033dff086bc81067ff0a4f5dff54434b5293aa9a/ui/file_manager/file_manager/background/js/volume_manager_impl.js
[modify] https://crrev.com/033dff086bc81067ff0a4f5dff54434b5293aa9a/ui/file_manager/file_manager/background/js/volume_manager_util.js
[modify] https://crrev.com/033dff086bc81067ff0a4f5dff54434b5293aa9a/ui/file_manager/file_manager/foreground/js/directory_model.js
[modify] https://crrev.com/033dff086bc81067ff0a4f5dff54434b5293aa9a/ui/file_manager/file_manager/foreground/js/file_manager.js
[modify] https://crrev.com/033dff086bc81067ff0a4f5dff54434b5293aa9a/ui/file_manager/integration_tests/file_manager/file_display.js

There isn't an easy way to test this manually.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/512139f8a5dfba65abc441b55973e1659eafcf87

commit 512139f8a5dfba65abc441b55973e1659eafcf87
Author: Luciano Pacheco <lucmult@chromium.org>
Date: Thu Oct 18 22:49:40 2018

Reland "Files app: Select My files when there are no volumes"

This reverts commit 103069350367d5c2cf85897e99e899b77a82f6b8.

Reason for revert: Undoing speculative revert
The CL was not the culprit

Original change's description:
> Revert "Files app: Select My files when there are no volumes"
>
> This reverts commit 6f65bd26330cf709e4a4c4eb60876de5849f94d5.
>
> Reason for revert: Speculative revert
> Suspected of breaking browser_tests, ebui_polymer2_browser_tests, single_process_mash_browser_tests and viz_browser_tests
> on Linux ChromiumOS MSan
>
> Note: resolved conflicts with ES6 refactoring, therefore running tests...
>
> Bug:  896219 
>
> Original change's description:
> > Files app: Select My files when there are no volumes
> >
> > Make Files app select "My files" when there are no available volumes,
> > this to allow Files app to behave properly when volumes subsequently
> > become available.
> >
> > Change DirectoryModel.onVolumeInfoListUpdated_ method to check for
> > non-null |displayRoot| before trying to change to |displayRoot|. This
> > fixes the error "Cannot read property 'getParent' of null" when Drive
> > volume becomes available before the (default) Downloads volume/root.
> >
> > Change FakeDriveFs to unbind the two mojo bindings if they're bound, so
> > DriveFsTestVolume can re-mount itself.
> >
> > Changes since revert:
> > 1. Add a new function |getVolumesCount| to return the number of volumes
> > available in the background page.
> > 2. Add the new function above to wait for background page to have all
> > volumes before un-mounting and wait it to unmount all volumes.
> > 3. Change some logs from error to warn because errors are expected and
> > handled when initializing volumes that are unmounting/unmounted in the
> > backend.
> > 4. Change selector used to click on Drive to actually wait for
> > "My Drive" to be available.
> > 5. A bit of more info in some logs around volume initialization.
> >
> > Test: browser_tests --gtest_filter="*/fileDisplayWithoutVolumesThenMount*"
> > Bug: 893161,  884967 ,  894799 
> > Change-Id: I7dcb340991750e9e79a9963990b614c6d7275890
> > Reviewed-on: https://chromium-review.googlesource.com/c/1278619
> > Reviewed-by: Noel Gordon <noel@chromium.org>
> > Reviewed-by: Sam McNally <sammc@chromium.org>
> > Commit-Queue: Luciano Pacheco <lucmult@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#600282}
>
> TBR=noel@chromium.org,sammc@chromium.org,lucmult@chromium.org
>
> Change-Id: Ifaadea8b49cffc6deb70b429a42bab39d4a3d52b
> Bug: 893161,  884967 ,  894799 
> Reviewed-on: https://chromium-review.googlesource.com/c/1286146
> Commit-Queue: Christos Froussios <cfroussios@chromium.org>
> Reviewed-by: Christos Froussios <cfroussios@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#600376}

TBR=noel@chromium.org,sammc@chromium.org,cfroussios@chromium.org,lucmult@chromium.org

Change-Id: I388a94fe12c7d40ac7ea779353c3b220bd5b5952
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug:  896219 , 893161,  884967 ,  894799 
Reviewed-on: https://chromium-review.googlesource.com/c/1286853
Reviewed-by: Christos Froussios <cfroussios@chromium.org>
Commit-Queue: Christos Froussios <cfroussios@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#600429}
Reviewed-on: https://chromium-review.googlesource.com/c/1287350
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Cr-Commit-Position: refs/branch-heads/3578@{#136}
Cr-Branched-From: 4226ddf99103e493d7afb23a4c7902ee496108b6-refs/heads/master@{#599034}
[modify] https://crrev.com/512139f8a5dfba65abc441b55973e1659eafcf87/ui/file_manager/file_manager/background/js/test_util_base.js
[modify] https://crrev.com/512139f8a5dfba65abc441b55973e1659eafcf87/ui/file_manager/file_manager/background/js/volume_manager_impl.js
[modify] https://crrev.com/512139f8a5dfba65abc441b55973e1659eafcf87/ui/file_manager/file_manager/background/js/volume_manager_util.js
[modify] https://crrev.com/512139f8a5dfba65abc441b55973e1659eafcf87/ui/file_manager/file_manager/foreground/js/directory_model.js
[modify] https://crrev.com/512139f8a5dfba65abc441b55973e1659eafcf87/ui/file_manager/file_manager/foreground/js/file_manager.js
[modify] https://crrev.com/512139f8a5dfba65abc441b55973e1659eafcf87/ui/file_manager/integration_tests/file_manager/file_display.js

The following revision refers to this bug: 
https://chromium.googlesource.com/chromium/src.git/+/512139f8a5dfba65abc441b55973e1659eafcf87

Commit: 512139f8a5dfba65abc441b55973e1659eafcf87
Author: lucmult@chromium.org
Commiter: lucmult@chromium.org
Date: 2018-10-18 22:49:40 +0000 UTC

Reland "Files app: Select My files when there are no volumes"

This reverts commit 103069350367d5c2cf85897e99e899b77a82f6b8.

Reason for revert: Undoing speculative revert
The CL was not the culprit

Original change's description:
> Revert "Files app: Select My files when there are no volumes"
>
> This reverts commit 6f65bd26330cf709e4a4c4eb60876de5849f94d5.
>
> Reason for revert: Speculative revert
> Suspected of breaking browser_tests, ebui_polymer2_browser_tests, single_process_mash_browser_tests and viz_browser_tests
> on Linux ChromiumOS MSan
>
> Note: resolved conflicts with ES6 refactoring, therefore running tests...
>
> Bug:  896219 
>
> Original change's description:
> > Files app: Select My files when there are no volumes
> >
> > Make Files app select "My files" when there are no available volumes,
> > this to allow Files app to behave properly when volumes subsequently
> > become available.
> >
> > Change DirectoryModel.onVolumeInfoListUpdated_ method to check for
> > non-null |displayRoot| before trying to change to |displayRoot|. This
> > fixes the error "Cannot read property 'getParent' of null" when Drive
> > volume becomes available before the (default) Downloads volume/root.
> >
> > Change FakeDriveFs to unbind the two mojo bindings if they're bound, so
> > DriveFsTestVolume can re-mount itself.
> >
> > Changes since revert:
> > 1. Add a new function |getVolumesCount| to return the number of volumes
> > available in the background page.
> > 2. Add the new function above to wait for background page to have all
> > volumes before un-mounting and wait it to unmount all volumes.
> > 3. Change some logs from error to warn because errors are expected and
> > handled when initializing volumes that are unmounting/unmounted in the
> > backend.
> > 4. Change selector used to click on Drive to actually wait for
> > "My Drive" to be available.
> > 5. A bit of more info in some logs around volume initialization.
> >
> > Test: browser_tests --gtest_filter="*/fileDisplayWithoutVolumesThenMount*"
> > Bug: 893161,  884967 ,  894799 
> > Change-Id: I7dcb340991750e9e79a9963990b614c6d7275890
> > Reviewed-on: https://chromium-review.googlesource.com/c/1278619
> > Reviewed-by: Noel Gordon <noel@chromium.org>
> > Reviewed-by: Sam McNally <sammc@chromium.org>
> > Commit-Queue: Luciano Pacheco <lucmult@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#600282}
>
> TBR=noel@chromium.org,sammc@chromium.org,lucmult@chromium.org
>
> Change-Id: Ifaadea8b49cffc6deb70b429a42bab39d4a3d52b
> Bug: 893161,  884967 ,  894799 
> Reviewed-on: https://chromium-review.googlesource.com/c/1286146
> Commit-Queue: Christos Froussios <cfroussios@chromium.org>
> Reviewed-by: Christos Froussios <cfroussios@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#600376}

TBR=noel@chromium.org,sammc@chromium.org,cfroussios@chromium.org,lucmult@chromium.org

Change-Id: I388a94fe12c7d40ac7ea779353c3b220bd5b5952
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug:  896219 , 893161,  884967 ,  894799 
Reviewed-on: https://chromium-review.googlesource.com/c/1286853
Reviewed-by: Christos Froussios <cfroussios@chromium.org>
Commit-Queue: Christos Froussios <cfroussios@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#600429}
Reviewed-on: https://chromium-review.googlesource.com/c/1287350
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Cr-Commit-Position: refs/branch-heads/3578@{#136}
Cr-Branched-From: 4226ddf99103e493d7afb23a4c7902ee496108b6-refs/heads/master@{#599034}