The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/635201011d3d7c4cccad0f31a571a153e3cf5694

commit 635201011d3d7c4cccad0f31a571a153e3cf5694
Author: David Bokan <bokan@chromium.org>
Date: Fri Jan 05 15:30:59 2018

Add implicit rootScroller feature

This patch adds an "implicit rootScroller" run-time flag. When turned
on, Blink can designate an element to be the rootScroller without the
page manually doing so using the rootScroller API (i.e.
document.rootScroller = myElement).

Currently, this will happen when an element is viewport-filling (is a
valid rootScroller) and, in the case of non-iframes, is explicitly
scrollable, having either overflow: auto or overflow: scroll. If there
are multiple elements that meet these conditions, the one with the
higher z-index wins. In the case of equal z-index - no rootScroller is
set implicitly.

This patch extends RootScrollerController by tracking a set of
"implicit candidates". As layout is performed, elements that meet the
requirements are added to this list (this is expected to be small). At
the end of layout, when we compute the effective root scroller, we
first iterate this set and decide on an implicit root scroller. If the
page didn't set an explicit root scroller, we use the implicit root
scroller, as if it were set via document.rootScroller.

Bug:  798719 
Change-Id: If6e68f9f17731c5cad7159e2df4284abeae43568
Reviewed-on: https://chromium-review.googlesource.com/841722
Reviewed-by: Steve Kobes <skobes@chromium.org>
Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Commit-Queue: David Bokan <bokan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#527281}
[modify] https://crrev.com/635201011d3d7c4cccad0f31a571a153e3cf5694/third_party/WebKit/LayoutTests/compositing/overflow/scrollbars-with-clipped-owner.html
[modify] https://crrev.com/635201011d3d7c4cccad0f31a571a153e3cf5694/third_party/WebKit/LayoutTests/paint/invalidation/resize-iframe-text.html
[modify] https://crrev.com/635201011d3d7c4cccad0f31a571a153e3cf5694/third_party/WebKit/Source/core/layout/LayoutBlock.cpp
[modify] https://crrev.com/635201011d3d7c4cccad0f31a571a153e3cf5694/third_party/WebKit/Source/core/layout/LayoutBox.cpp
[modify] https://crrev.com/635201011d3d7c4cccad0f31a571a153e3cf5694/third_party/WebKit/Source/core/layout/LayoutIFrame.cpp
[modify] https://crrev.com/635201011d3d7c4cccad0f31a571a153e3cf5694/third_party/WebKit/Source/core/layout/LayoutIFrame.h
[modify] https://crrev.com/635201011d3d7c4cccad0f31a571a153e3cf5694/third_party/WebKit/Source/core/page/scrolling/RootScrollerController.cpp
[modify] https://crrev.com/635201011d3d7c4cccad0f31a571a153e3cf5694/third_party/WebKit/Source/core/page/scrolling/RootScrollerController.h
[modify] https://crrev.com/635201011d3d7c4cccad0f31a571a153e3cf5694/third_party/WebKit/Source/core/page/scrolling/RootScrollerTest.cpp
[modify] https://crrev.com/635201011d3d7c4cccad0f31a571a153e3cf5694/third_party/WebKit/Source/platform/runtime_enabled_features.json5

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b8a6743f5947a83a1618f01a50f6aad3ee70769d

commit b8a6743f5947a83a1618f01a50f6aad3ee70769d
Author: Mike Wittman <wittman@chromium.org>
Date: Fri Jan 05 18:37:01 2018

Revert "Add implicit rootScroller feature"

This reverts commit 635201011d3d7c4cccad0f31a571a153e3cf5694.

Reason for revert: Suspected of causing WebKit Linux Trusty Leak webkit_layout_tests failures in virtual/android/fullscreen/video-scrolled-iframe.html

08:04:30.229 24767 [1/1] virtual/android/fullscreen/video-scrolled-iframe.html failed unexpectedly (image diff)

https://uberchromegw.corp.google.com/i/chromium.webkit/builders/WebKit%20Linux%20Trusty%20Leak/builds/13992


Original change's description:
> Add implicit rootScroller feature
> 
> This patch adds an "implicit rootScroller" run-time flag. When turned
> on, Blink can designate an element to be the rootScroller without the
> page manually doing so using the rootScroller API (i.e.
> document.rootScroller = myElement).
> 
> Currently, this will happen when an element is viewport-filling (is a
> valid rootScroller) and, in the case of non-iframes, is explicitly
> scrollable, having either overflow: auto or overflow: scroll. If there
> are multiple elements that meet these conditions, the one with the
> higher z-index wins. In the case of equal z-index - no rootScroller is
> set implicitly.
> 
> This patch extends RootScrollerController by tracking a set of
> "implicit candidates". As layout is performed, elements that meet the
> requirements are added to this list (this is expected to be small). At
> the end of layout, when we compute the effective root scroller, we
> first iterate this set and decide on an implicit root scroller. If the
> page didn't set an explicit root scroller, we use the implicit root
> scroller, as if it were set via document.rootScroller.
> 
> Bug:  798719 
> Change-Id: If6e68f9f17731c5cad7159e2df4284abeae43568
> Reviewed-on: https://chromium-review.googlesource.com/841722
> Reviewed-by: Steve Kobes <skobes@chromium.org>
> Reviewed-by: Jeremy Roman <jbroman@chromium.org>
> Commit-Queue: David Bokan <bokan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#527281}

TBR=bokan@chromium.org,jbroman@chromium.org,skobes@chromium.org

Change-Id: I55bd27f941120f16924e1d12459384078f4d3aba
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug:  798719 
Reviewed-on: https://chromium-review.googlesource.com/852794
Reviewed-by: Mike Wittman <wittman@chromium.org>
Commit-Queue: Mike Wittman <wittman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#527330}
[modify] https://crrev.com/b8a6743f5947a83a1618f01a50f6aad3ee70769d/third_party/WebKit/LayoutTests/compositing/overflow/scrollbars-with-clipped-owner.html
[modify] https://crrev.com/b8a6743f5947a83a1618f01a50f6aad3ee70769d/third_party/WebKit/LayoutTests/paint/invalidation/resize-iframe-text.html
[modify] https://crrev.com/b8a6743f5947a83a1618f01a50f6aad3ee70769d/third_party/WebKit/Source/core/layout/LayoutBlock.cpp
[modify] https://crrev.com/b8a6743f5947a83a1618f01a50f6aad3ee70769d/third_party/WebKit/Source/core/layout/LayoutBox.cpp
[modify] https://crrev.com/b8a6743f5947a83a1618f01a50f6aad3ee70769d/third_party/WebKit/Source/core/layout/LayoutIFrame.cpp
[modify] https://crrev.com/b8a6743f5947a83a1618f01a50f6aad3ee70769d/third_party/WebKit/Source/core/layout/LayoutIFrame.h
[modify] https://crrev.com/b8a6743f5947a83a1618f01a50f6aad3ee70769d/third_party/WebKit/Source/core/page/scrolling/RootScrollerController.cpp
[modify] https://crrev.com/b8a6743f5947a83a1618f01a50f6aad3ee70769d/third_party/WebKit/Source/core/page/scrolling/RootScrollerController.h
[modify] https://crrev.com/b8a6743f5947a83a1618f01a50f6aad3ee70769d/third_party/WebKit/Source/core/page/scrolling/RootScrollerTest.cpp
[modify] https://crrev.com/b8a6743f5947a83a1618f01a50f6aad3ee70769d/third_party/WebKit/Source/platform/runtime_enabled_features.json5

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3f0b9946f52dc4e146e90e7377974e12a76404b5

commit 3f0b9946f52dc4e146e90e7377974e12a76404b5
Author: David Bokan <bokan@chromium.org>
Date: Mon Jan 22 15:29:23 2018

Fix rootScroller when iframe's view is swapped.

This CL fixes an issue when the rootScroller is set to an iframe. An
iframe is a special case for rootScroller and requires some changes to
be made on the FrameView. This happens in
RootScrollerController::ApplyRootScrollerProperties. However, in some
cases, when the iframe is navigated we can end up swapping the FrameView
used by the Frame. Currently, we don't call ApplyRootScrollerProperties
on it since the effective rootScroller in the parent document hasn't
changed.

This CL adds a hook in HTMLFrameOwnerElement to let the
RootScrollerController know that it needs to reapply any properties
on the FrameView. I added a test set-rootscroller-before-load.html that
exercises this case.

A related change also fixes  issue 799577  which is caused by differences
in (frame_owner->ContentFrame())->View() and
frame_owner->OwnedEmbeddedContentView(). This CL change
ApplyRootScrollerProperties to use the latter.

I also made a small change to the older nested-rootscroller* tests to
deflake them.

Bug:  798719 ,  799577 
Change-Id: I1c1ba8ed3d2be80fbbfbb16e8c17e1734b066801
Reviewed-on: https://chromium-review.googlesource.com/867652
Commit-Queue: David Bokan <bokan@chromium.org>
Reviewed-by: Steve Kobes <skobes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#530868}
[add] https://crrev.com/3f0b9946f52dc4e146e90e7377974e12a76404b5/third_party/WebKit/LayoutTests/rootscroller/set-rootscroller-before-load-expected.html
[add] https://crrev.com/3f0b9946f52dc4e146e90e7377974e12a76404b5/third_party/WebKit/LayoutTests/rootscroller/set-rootscroller-before-load.html
[modify] https://crrev.com/3f0b9946f52dc4e146e90e7377974e12a76404b5/third_party/WebKit/LayoutTests/virtual/android/rootscroller/nested-rootscroller-browser-controls-bounds-hidden.html
[modify] https://crrev.com/3f0b9946f52dc4e146e90e7377974e12a76404b5/third_party/WebKit/LayoutTests/virtual/android/rootscroller/nested-rootscroller-browser-controls-bounds-shown.html
[modify] https://crrev.com/3f0b9946f52dc4e146e90e7377974e12a76404b5/third_party/WebKit/Source/core/html/HTMLFrameOwnerElement.cpp
[modify] https://crrev.com/3f0b9946f52dc4e146e90e7377974e12a76404b5/third_party/WebKit/Source/core/page/scrolling/RootScrollerController.cpp
[modify] https://crrev.com/3f0b9946f52dc4e146e90e7377974e12a76404b5/third_party/WebKit/Source/core/page/scrolling/RootScrollerController.h
[modify] https://crrev.com/3f0b9946f52dc4e146e90e7377974e12a76404b5/third_party/WebKit/Source/core/page/scrolling/TopDocumentRootScrollerController.cpp
[modify] https://crrev.com/3f0b9946f52dc4e146e90e7377974e12a76404b5/third_party/WebKit/Source/core/testing/Internals.cpp
[modify] https://crrev.com/3f0b9946f52dc4e146e90e7377974e12a76404b5/third_party/WebKit/Source/core/testing/Internals.h
[modify] https://crrev.com/3f0b9946f52dc4e146e90e7377974e12a76404b5/third_party/WebKit/Source/core/testing/Internals.idl

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9624739f0ef77cff687240e322d0e3d43d7cf0cf

commit 9624739f0ef77cff687240e322d0e3d43d7cf0cf
Author: David Bokan <bokan@chromium.org>
Date: Mon Jan 22 16:20:36 2018

Disable rootScroller while in fullscreen

This change caused the revert of r527281 since fullscreen tests would
cause elements to fill the viewport and become implicitly promoted to
rootScroller. This caused differences in test due to scrollbars.

This CL disables rootScroller selection (implicit and explicit) when
the document is fullscreen.

Bug:  798719 
Change-Id: If1ad82d017e102d7f1248fc623f84667ce45bdaa
Reviewed-on: https://chromium-review.googlesource.com/867519
Commit-Queue: David Bokan <bokan@chromium.org>
Reviewed-by: Steve Kobes <skobes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#530876}
[add] https://crrev.com/9624739f0ef77cff687240e322d0e3d43d7cf0cf/third_party/WebKit/LayoutTests/rootscroller/rootscroller-during-fullscreen.html
[modify] https://crrev.com/9624739f0ef77cff687240e322d0e3d43d7cf0cf/third_party/WebKit/Source/core/page/scrolling/RootScrollerController.cpp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e9aa1ff150cc50a295227f280d50a7b023938cbd

commit e9aa1ff150cc50a295227f280d50a7b023938cbd
Author: David Bokan <bokan@chromium.org>
Date: Mon Jan 22 18:56:02 2018

[Reland] Add implicit rootScroller feature

This patch adds an "implicit rootScroller" run-time flag. When turned
on, Blink can designate an element to be the rootScroller without the
page manually doing so using the rootScroller API (i.e.
document.rootScroller = myElement).

Currently, this will happen when an element is viewport-filling (is a
valid rootScroller) and, in the case of non-iframes, is explicitly
scrollable, having either overflow: auto or overflow: scroll. If there
are multiple elements that meet these conditions, the one with the
higher z-index wins. In the case of equal z-index - no rootScroller is
set implicitly.

This patch extends RootScrollerController by tracking a set of
"implicit candidates". As layout is performed, elements that meet the
requirements are added to this list (this is expected to be small). At
the end of layout, when we compute the effective root scroller, we
first iterate this set and decide on an implicit root scroller. If the
page didn't set an explicit root scroller, we use the implicit root
scroller, as if it were set via document.rootScroller.

[Reland] Originally landed in r527281 and reverted in r527330. This
CL is relanded after two fixes

1) https://crrev.com/c/867652 fixes issues with iframes not being
correctly updated when their FrameView is swapped
2) https://crrev.com/c/867519 prevents elements from being promoted
while the document is in fullscreen.

TBR=skobes@chromium.org,jbroman@chromium.org

Bug:  798719 
Change-Id: I16ce1e3589775281bb7c5bc6c9c2731a56433fb0
Reviewed-on: https://chromium-review.googlesource.com/862082
Reviewed-by: David Bokan <bokan@chromium.org>
Commit-Queue: David Bokan <bokan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#530927}
[modify] https://crrev.com/e9aa1ff150cc50a295227f280d50a7b023938cbd/third_party/WebKit/LayoutTests/compositing/overflow/scrollbars-with-clipped-owner.html
[modify] https://crrev.com/e9aa1ff150cc50a295227f280d50a7b023938cbd/third_party/WebKit/LayoutTests/paint/invalidation/resize-iframe-text.html
[modify] https://crrev.com/e9aa1ff150cc50a295227f280d50a7b023938cbd/third_party/WebKit/Source/core/layout/LayoutBlock.cpp
[modify] https://crrev.com/e9aa1ff150cc50a295227f280d50a7b023938cbd/third_party/WebKit/Source/core/layout/LayoutBox.cpp
[modify] https://crrev.com/e9aa1ff150cc50a295227f280d50a7b023938cbd/third_party/WebKit/Source/core/layout/LayoutIFrame.cpp
[modify] https://crrev.com/e9aa1ff150cc50a295227f280d50a7b023938cbd/third_party/WebKit/Source/core/layout/LayoutIFrame.h
[modify] https://crrev.com/e9aa1ff150cc50a295227f280d50a7b023938cbd/third_party/WebKit/Source/core/page/scrolling/RootScrollerController.cpp
[modify] https://crrev.com/e9aa1ff150cc50a295227f280d50a7b023938cbd/third_party/WebKit/Source/core/page/scrolling/RootScrollerController.h
[modify] https://crrev.com/e9aa1ff150cc50a295227f280d50a7b023938cbd/third_party/WebKit/Source/core/page/scrolling/RootScrollerTest.cpp
[modify] https://crrev.com/e9aa1ff150cc50a295227f280d50a7b023938cbd/third_party/WebKit/Source/platform/runtime_enabled_features.json5

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c0ae9747fa4a6093f47837bb13ed0c39636af251

commit c0ae9747fa4a6093f47837bb13ed0c39636af251
Author: David Bokan <bokan@chromium.org>
Date: Wed May 02 21:25:17 2018

Make root scroller valid in both URL bar states

Some pages resize their main scroller to the viewport height as the
URL bar is shown and hidden. In those cases, we should allow a valid
root scroller at both heights.  Otherwise, when the URL bar is hidden
and the scroller resizes, it'll be demoted and the user will have to
scroll all the way to the top to show the URL bar again. Currently,
the root scroller must exactly match the initial containing block
which does not resize in response to the URL bar.

An obvious question would be why allow either height, rather than
calculating the current viewport height and using that. In most cases
a scroller we want to promote will not resize its height and we still
want to keep those scrollers promoted.

Bug:  798719 
Change-Id: I11684ee5115a02f1f65868399f58074df43e764f
Reviewed-on: https://chromium-review.googlesource.com/1036287
Commit-Queue: David Bokan <bokan@chromium.org>
Reviewed-by: Philip Rogers <pdr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555555}
[modify] https://crrev.com/c0ae9747fa4a6093f47837bb13ed0c39636af251/third_party/blink/renderer/core/frame/local_frame_view.cc
[modify] https://crrev.com/c0ae9747fa4a6093f47837bb13ed0c39636af251/third_party/blink/renderer/core/page/scrolling/root_scroller_controller.cc
[modify] https://crrev.com/c0ae9747fa4a6093f47837bb13ed0c39636af251/third_party/blink/renderer/core/page/scrolling/root_scroller_test.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9dd6125107e9644f9276c6e724efcacfce3e2aae

commit 9dd6125107e9644f9276c6e724efcacfce3e2aae
Author: David Bokan <bokan@chromium.org>
Date: Fri May 04 23:27:15 2018

[root-scroller] Remove check for layout phase

This check existed because changing the root scroller used to require
synchronously calling UpdateLayoutAndStyle which would reach up and
dirty layout in an ancestor frame. This violated the lifecycle because
updating the root scroller can happen from the ancestor's layout.

Since we no longer need to recompute style (root scroller used to change
the background style), this is no longer needed. Test added to verify.

For a detailed description of how this could happen, see:
https://crrev.com/6f14d2bf37f56f73d1875b5c15298c70b77c4dac

Bug:  798719 
Change-Id: I40cba8d8564d7365b4c7815bb6cfca7a1ad6d76c
Reviewed-on: https://chromium-review.googlesource.com/1044363
Reviewed-by: Philip Rogers <pdr@chromium.org>
Commit-Queue: David Bokan <bokan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#556244}
[modify] https://crrev.com/9dd6125107e9644f9276c6e724efcacfce3e2aae/third_party/blink/renderer/core/page/scrolling/root_scroller_controller.cc
[modify] https://crrev.com/9dd6125107e9644f9276c6e724efcacfce3e2aae/third_party/blink/renderer/core/page/scrolling/root_scroller_test.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/59f28009d74de2ffde98b388226264207db776ab

commit 59f28009d74de2ffde98b388226264207db776ab
Author: David Bokan <bokan@chromium.org>
Date: Thu Oct 18 14:08:54 2018

Convert root scroller HitTesting tests to SimTest

Bug:  798719 
Change-Id: I371d41833373fe54efeb844a338840b7d862784c
Reviewed-on: https://chromium-review.googlesource.com/c/1287188
Reviewed-by: Dave Tapuska <dtapuska@chromium.org>
Commit-Queue: David Bokan <bokan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600753}
[modify] https://crrev.com/59f28009d74de2ffde98b388226264207db776ab/third_party/blink/renderer/core/page/scrolling/root_scroller_test.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5358154a493c5736fc1a4f225128802c08e05b11

commit 5358154a493c5736fc1a4f225128802c08e05b11
Author: David Bokan <bokan@chromium.org>
Date: Tue Nov 06 03:51:32 2018

Fix hit test when using rootScroller

When an Element is made the global rootScroller, it can hide the URL bar
like Document scrolling does normally. However, the Element's LayoutBox,
like the LayoutView, is not resized in this case. This means there's a
newly exposed region at the bottom of the screen that's visible beyond
the Element's overflow rect.

LayoutView already has an exception in the PaintLayerClipper for this
case. This CL extends the exception to the root scroller. This fixes hit
testing that descends into child PaintLayers of the root scroller's
layer.

In addition, it also caches an "IsGlobalRootScroller" bit in
LayoutObject for performance, just like the effective bit added in
https://crrev.com/2685a6b3e82be7711c6d3b02f225b1b90bb9bf46

Also added tests to ensure this works in an iframe.

Bug:  798719 
Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_slimming_paint_v2;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: Iaf87db5569ebbe1aa82f20d3cf19868a12ed9539
Reviewed-on: https://chromium-review.googlesource.com/c/1287176
Commit-Queue: David Bokan <bokan@chromium.org>
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#605587}
[modify] https://crrev.com/5358154a493c5736fc1a4f225128802c08e05b11/third_party/blink/renderer/core/dom/node.cc
[modify] https://crrev.com/5358154a493c5736fc1a4f225128802c08e05b11/third_party/blink/renderer/core/input/scroll_manager.cc
[modify] https://crrev.com/5358154a493c5736fc1a4f225128802c08e05b11/third_party/blink/renderer/core/layout/layout_object.h
[modify] https://crrev.com/5358154a493c5736fc1a4f225128802c08e05b11/third_party/blink/renderer/core/page/scrolling/root_scroller_test.cc
[modify] https://crrev.com/5358154a493c5736fc1a4f225128802c08e05b11/third_party/blink/renderer/core/page/scrolling/root_scroller_util.cc
[modify] https://crrev.com/5358154a493c5736fc1a4f225128802c08e05b11/third_party/blink/renderer/core/page/scrolling/root_scroller_util.h
[modify] https://crrev.com/5358154a493c5736fc1a4f225128802c08e05b11/third_party/blink/renderer/core/page/scrolling/top_document_root_scroller_controller.cc
[modify] https://crrev.com/5358154a493c5736fc1a4f225128802c08e05b11/third_party/blink/renderer/core/page/scrolling/top_document_root_scroller_controller.h
[modify] https://crrev.com/5358154a493c5736fc1a4f225128802c08e05b11/third_party/blink/renderer/core/paint/compositing/compositing_reason_finder.cc
[modify] https://crrev.com/5358154a493c5736fc1a4f225128802c08e05b11/third_party/blink/renderer/core/paint/paint_layer_clipper.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0d1087c7da1b20c8cb3de32890b05102513b6200

commit 0d1087c7da1b20c8cb3de32890b05102513b6200
Author: David Bokan <bokan@chromium.org>
Date: Thu Nov 08 12:55:15 2018

Enable implicit root scroller in stable

Bug:  798719 
Change-Id: I05c0bc89c3e842f005be57db2226b4188ee4da3b
Reviewed-on: https://chromium-review.googlesource.com/c/1320812
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: David Bokan <bokan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606428}
[modify] https://crrev.com/0d1087c7da1b20c8cb3de32890b05102513b6200/third_party/blink/renderer/platform/runtime_enabled_features.json5

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/98c0da5ef75600bf789b5c13b7f80fd848b1579d

commit 98c0da5ef75600bf789b5c13b7f80fd848b1579d
Author: David Bokan <bokan@chromium.org>
Date: Thu Nov 08 14:59:51 2018

Add use counter for implicit root scroller

Bug:  798719 
Change-Id: Iee4735a21292c8de2d5f638358844a3b279f92d5
Reviewed-on: https://chromium-review.googlesource.com/c/1320193
Commit-Queue: David Bokan <bokan@chromium.org>
Reviewed-by: Dave Tapuska <dtapuska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606463}
[modify] https://crrev.com/98c0da5ef75600bf789b5c13b7f80fd848b1579d/third_party/blink/public/platform/web_feature.mojom
[modify] https://crrev.com/98c0da5ef75600bf789b5c13b7f80fd848b1579d/third_party/blink/renderer/core/page/scrolling/root_scroller_controller.cc
[modify] https://crrev.com/98c0da5ef75600bf789b5c13b7f80fd848b1579d/third_party/blink/renderer/core/page/scrolling/root_scroller_test.cc
[modify] https://crrev.com/98c0da5ef75600bf789b5c13b7f80fd848b1579d/tools/metrics/histograms/enums.xml

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9deef45cc5f77319506088554cd40aa521e9df8d

commit 9deef45cc5f77319506088554cd40aa521e9df8d
Author: David Bokan <bokan@chromium.org>
Date: Tue Nov 27 16:15:58 2018

Revert "Enable implicit root scroller in stable"

This reverts commit 0d1087c7da1b20c8cb3de32890b05102513b6200.

Reason for revert: Feature isn't approved to ship - was turned on to get some early data in Canary/Dev

Original change's description:
> Enable implicit root scroller in stable
> 
> Bug:  798719 
> Change-Id: I05c0bc89c3e842f005be57db2226b4188ee4da3b
> Reviewed-on: https://chromium-review.googlesource.com/c/1320812
> Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
> Commit-Queue: David Bokan <bokan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#606428}

TBR=bokan@chromium.org,chrishtr@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug:  798719 
Change-Id: I9fb19298e818fc21bfd42404253a5110a226246e
Reviewed-on: https://chromium-review.googlesource.com/c/1351604
Reviewed-by: David Bokan <bokan@chromium.org>
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: David Bokan <bokan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611133}
[modify] https://crrev.com/9deef45cc5f77319506088554cd40aa521e9df8d/third_party/blink/renderer/platform/runtime_enabled_features.json5