Copied  issue chromium:850743  to  issue chromium:852145 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ad910ae2f13f930e5db7dcb7a28fc1ab215513eb

commit ad910ae2f13f930e5db7dcb7a28fc1ab215513eb
Author: Kevin Marshall <kmarshall@chromium.org>
Date: Sat Jun 16 05:40:53 2018

Fuchsia: Enable mounting handles as dirs on child processess.

This functionality will be used by the ContextProvider service to
bind an arbitrary, client-supplied directory handle to the "/data"
directory of the child Context processes.

* Adds a helper function for extracting file handles from File objects.
* Adds unit tests.
* Migrates some uses of ScopedZxHandle to zx::handle.

Bug:  850743 ,  852541 
Change-Id: Iada1775485745124822e32b9ac81aefaff6b9059
Reviewed-on: https://chromium-review.googlesource.com/1091803
Commit-Queue: Kevin Marshall <kmarshall@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Reviewed-by: Sergey Ulanov <sergeyu@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567880}
[modify] https://crrev.com/ad910ae2f13f930e5db7dcb7a28fc1ab215513eb/base/BUILD.gn
[add] https://crrev.com/ad910ae2f13f930e5db7dcb7a28fc1ab215513eb/base/fuchsia/file_utils.cc
[add] https://crrev.com/ad910ae2f13f930e5db7dcb7a28fc1ab215513eb/base/fuchsia/file_utils.h
[modify] https://crrev.com/ad910ae2f13f930e5db7dcb7a28fc1ab215513eb/base/process/launch.h
[modify] https://crrev.com/ad910ae2f13f930e5db7dcb7a28fc1ab215513eb/base/process/launch_fuchsia.cc
[modify] https://crrev.com/ad910ae2f13f930e5db7dcb7a28fc1ab215513eb/base/process/process_util_unittest.cc
[modify] https://crrev.com/ad910ae2f13f930e5db7dcb7a28fc1ab215513eb/content/common/sandbox_policy_fuchsia.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/323013a9ed3130764689ff4fcfdde58f2e5cf041

commit 323013a9ed3130764689ff4fcfdde58f2e5cf041
Author: Kevin Marshall <kmarshall@chromium.org>
Date: Mon Jun 18 21:02:14 2018

Fuchsia: Implement spawning portions of ContextProvider FIDL service.

Implements and tests the Context child process spawning aspects of
ContextProvider.

Additionally moves non-main portions of "//webrunner:webrunner" into a
component, so that they can be called from unit tests.

Bug:  850743 
Change-Id: I4f4aafac71ac56d72c6931db3751201bc516d92a
Reviewed-on: https://chromium-review.googlesource.com/1096453
Commit-Queue: Kevin Marshall <kmarshall@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Reviewed-by: Sergey Ulanov <sergeyu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568161}
[modify] https://crrev.com/323013a9ed3130764689ff4fcfdde58f2e5cf041/BUILD.gn
[modify] https://crrev.com/323013a9ed3130764689ff4fcfdde58f2e5cf041/webrunner/BUILD.gn
[modify] https://crrev.com/323013a9ed3130764689ff4fcfdde58f2e5cf041/webrunner/app/DEPS
[add] https://crrev.com/323013a9ed3130764689ff4fcfdde58f2e5cf041/webrunner/app/context_provider/context_provider_impl.cc
[add] https://crrev.com/323013a9ed3130764689ff4fcfdde58f2e5cf041/webrunner/app/context_provider/context_provider_impl.h
[add] https://crrev.com/323013a9ed3130764689ff4fcfdde58f2e5cf041/webrunner/app/context_provider/context_provider_impl_unittest.cc
[add] https://crrev.com/323013a9ed3130764689ff4fcfdde58f2e5cf041/webrunner/app/switches.cc
[add] https://crrev.com/323013a9ed3130764689ff4fcfdde58f2e5cf041/webrunner/app/switches.h
[modify] https://crrev.com/323013a9ed3130764689ff4fcfdde58f2e5cf041/webrunner/app/webrunner_main_delegate.h
[add] https://crrev.com/323013a9ed3130764689ff4fcfdde58f2e5cf041/webrunner/common/webrunner_export.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a7c1e6c93e9232f41f9f83c6ea1d1b42ef3bf980

commit a7c1e6c93e9232f41f9f83c6ea1d1b42ef3bf980
Author: Sergey Ulanov <sergeyu@chromium.org>
Date: Tue Jul 24 19:53:29 2018

[Fuchsia] Don't bind ComponentControllerImpl twice.

Previously ComponentControllerImpl::BindToRequest() was called twice,
so the Context process was crashing.

Bug:  850743 
Change-Id: I7fe63558afcf586beb1380ce0d108458e1532f9b
Reviewed-on: https://chromium-review.googlesource.com/1147551
Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577646}
[modify] https://crrev.com/a7c1e6c93e9232f41f9f83c6ea1d1b42ef3bf980/webrunner/app/component_controller_impl.h
[modify] https://crrev.com/a7c1e6c93e9232f41f9f83c6ea1d1b42ef3bf980/webrunner/app/web_content_runner.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/54f61462b4e9f09f37ec4760181464b74a3a31af

commit 54f61462b4e9f09f37ec4760181464b74a3a31af
Author: Sergey Ulanov <sergeyu@chromium.org>
Date: Tue Jul 24 20:27:47 2018

[Fuchsia] Disable GPU in webrunner

Now ContextProvider will run Context process with --disable-gpu.
GPU process doesn't work correctly on Fuchsia yet.

Bug:  850743 , 867052
Change-Id: Ifde22a36beb69f187be07b7fd075a0f8d807bcdf
Reviewed-on: https://chromium-review.googlesource.com/1147550
Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577663}
[modify] https://crrev.com/54f61462b4e9f09f37ec4760181464b74a3a31af/webrunner/service/context_provider_impl.cc