Create single thread synchronous task graph runner when necessary with gpu disabled.

Create single thread synchronous task graph runner when necessary with gpu disabled.

This prevents layout tests from crashing with --disable-gpu

Committed: https://crrev.com/8546cb1249babdd05de341cc30a95bec99253f2c
Cr-Commit-Position: refs/heads/master@{#329960}

[jbauman, 2015-05-14 00:36:05]

jbauman@chromium.org changed reviewers:
+ hendrikw@chromium.org, vmpstr@chromium.org

[hendrikw, 2015-05-14 00:39:06]

On 2015/05/14 00:36:05, jbauman wrote:

LGTM

[vmpstr, 2015-05-14 20:00:19]

https://codereview.chromium.org/1135943006/diff/1/cc/trees/layer_tree_host_im...
File cc/trees/layer_tree_host_impl.cc (right):

https://codereview.chromium.org/1135943006/diff/1/cc/trees/layer_tree_host_im...
cc/trees/layer_tree_host_impl.cc:2056: task_runner, task_graph_runner_,
resource_provider_.get());
Is this supposed to be using task_graph_runner (the local variable)?

I don't understand why this is fixing it. Is it the fact that we use
single_thread_synchronous_task_graph_runner_ directly somewhere? and
tile_Task_worker_pool doesn't really matter?

[jbauman, 2015-05-14 21:45:27]

PTAL

On 2015/05/14 20:00:19, vmpstr wrote:
>
https://codereview.chromium.org/1135943006/diff/1/cc/trees/layer_tree_host_im...
> File cc/trees/layer_tree_host_impl.cc (right):
> 
>
https://codereview.chromium.org/1135943006/diff/1/cc/trees/layer_tree_host_im...
> cc/trees/layer_tree_host_impl.cc:2056: task_runner, task_graph_runner_,
> resource_provider_.get());
> Is this supposed to be using task_graph_runner (the local variable)?
> 
Oops, fixed.

> I don't understand why this is fixing it. Is it the fact that we use
> single_thread_synchronous_task_graph_runner_ directly somewhere? and
> tile_Task_worker_pool doesn't really matter?

The crash was due to single_thread_synchronous_task_graph_runner_ being null and
being used somewhere.

[vmpstr, 2015-05-14 22:02:12]

lgtm

[jbauman, 2015-05-14 22:03:16]

The CQ bit was checked by jbauman@chromium.org

[jbauman, 2015-05-14 22:03:16]

The patchset sent to the CQ was uploaded after l-g-t-m from
hendrikw@chromium.org
Link to the patchset: https://codereview.chromium.org/1135943006/#ps20001
(title: " ")

[commit-bot: I haz the power, 2015-05-14 22:05:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1135943006/20001

[commit-bot: I haz the power, 2015-05-14 22:39:00]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-05-14 22:40:47]

Patchset 2 (id:??) landed as
https://crrev.com/8546cb1249babdd05de341cc30a95bec99253f2c
Cr-Commit-Position: refs/heads/master@{#329960}