vmpstr@, do you know whether we can remove this?

Yeah I think this is a good path forward. This should be a two step process, first we'd enable it in ui compositor and monitor any perf changes (there shouldn't be any). If that lands and sticks, we can remove the flag altogether.

khushalsagar@, did you want to take a look at this or did you want me to?

I don't think I'll have time soon to look into this one. Feel free to take it. :)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/979cc161d997ca6f73b6dfeecb7f2a225b1c8140

commit 979cc161d997ca6f73b6dfeecb7f2a225b1c8140
Author: vmpstr <vmpstr@chromium.org>
Date: Wed Mar 15 18:22:08 2017

ui/compositor: Enable image decode tasks in the UI compositor.

This patch is the first step to removing the flag from the codebase.
The UI compositor is the only place that sets this to false, but it
shouldn't hurt performance with or without the flag. In order to
verify this, this patch only enables the flag. If the perf bots are
happy with the change, we'll remove the flag altogether.

R=danakj@chromium.org
BUG=696864

Review-Url: https://codereview.chromium.org/2736303002
Cr-Commit-Position: refs/heads/master@{#457144}

[modify] https://crrev.com/979cc161d997ca6f73b6dfeecb7f2a225b1c8140/ui/compositor/compositor.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5cff918de35f1a3379d8fce7984eef770e1e2d44

commit 5cff918de35f1a3379d8fce7984eef770e1e2d44
Author: vmpstr <vmpstr@chromium.org>
Date: Thu Apr 27 17:48:35 2017

Remove image_decode_tasks_enabled flag.

This flag should be on by default in all non-test cases, so this patch
removes the flag altogether.

BUG=696864
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Review-Url: https://codereview.chromium.org/2781183002
Cr-Commit-Position: refs/heads/master@{#467725}

[modify] https://crrev.com/5cff918de35f1a3379d8fce7984eef770e1e2d44/cc/layers/picture_layer.cc
[modify] https://crrev.com/5cff918de35f1a3379d8fce7984eef770e1e2d44/cc/layers/picture_layer_unittest.cc
[modify] https://crrev.com/5cff918de35f1a3379d8fce7984eef770e1e2d44/cc/layers/recording_source.cc
[modify] https://crrev.com/5cff918de35f1a3379d8fce7984eef770e1e2d44/cc/layers/recording_source.h
[modify] https://crrev.com/5cff918de35f1a3379d8fce7984eef770e1e2d44/cc/layers/recording_source_unittest.cc
[modify] https://crrev.com/5cff918de35f1a3379d8fce7984eef770e1e2d44/cc/raster/raster_source_unittest.cc
[modify] https://crrev.com/5cff918de35f1a3379d8fce7984eef770e1e2d44/cc/test/fake_recording_source.cc
[modify] https://crrev.com/5cff918de35f1a3379d8fce7984eef770e1e2d44/cc/tiles/tile_manager_unittest.cc
[modify] https://crrev.com/5cff918de35f1a3379d8fce7984eef770e1e2d44/cc/trees/layer_tree_host.cc
[modify] https://crrev.com/5cff918de35f1a3379d8fce7984eef770e1e2d44/cc/trees/layer_tree_host_impl_unittest.cc
[modify] https://crrev.com/5cff918de35f1a3379d8fce7984eef770e1e2d44/cc/trees/layer_tree_host_unittest.cc
[modify] https://crrev.com/5cff918de35f1a3379d8fce7984eef770e1e2d44/cc/trees/layer_tree_host_unittest_checkerimaging.cc
[modify] https://crrev.com/5cff918de35f1a3379d8fce7984eef770e1e2d44/cc/trees/layer_tree_settings.h
[modify] https://crrev.com/5cff918de35f1a3379d8fce7984eef770e1e2d44/content/renderer/gpu/compositor_dependencies.h
[modify] https://crrev.com/5cff918de35f1a3379d8fce7984eef770e1e2d44/content/renderer/gpu/render_widget_compositor.cc
[modify] https://crrev.com/5cff918de35f1a3379d8fce7984eef770e1e2d44/content/renderer/render_thread_impl.cc
[modify] https://crrev.com/5cff918de35f1a3379d8fce7984eef770e1e2d44/content/renderer/render_thread_impl.h
[modify] https://crrev.com/5cff918de35f1a3379d8fce7984eef770e1e2d44/content/test/fake_compositor_dependencies.cc
[modify] https://crrev.com/5cff918de35f1a3379d8fce7984eef770e1e2d44/content/test/fake_compositor_dependencies.h
[modify] https://crrev.com/5cff918de35f1a3379d8fce7984eef770e1e2d44/ui/compositor/compositor.cc