Remove WebCompositorSupport::initialize/shutdown dependency from webkit_support::CreateLayerTreeView

Remove WebCompositorSupport::initialize/shutdown dependency from webkit_support::CreateLayerTreeView

webkit_support::CreateLayerTreeView is used by WebViewHost to construct
compositor instances for DumpRenderTree to use in layout tests. This
code creates and manages the thread used for compositor (in TestShell)
and can pass it directly into the Create..() calls without needing to
register it on WebCompositorSupport. This is closer to what the production
code (in content::RenderWidgetCompositor) does.

This adds a new entry point where the caller specifies the thread. After this
lands and rolls into WebKit, I'll migrate WebViewHost to call the new function
and after that rolls into Chromium remove these deprecated versions along with
WebCompositorSupport::initialize/shutdown.

R=enne@chromium.org


Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=185963

[jamesr, 2013-03-04 06:16:19]

Gets rid of some static state and tightens up an interface.  Woohoo!

[enne (OOO), 2013-03-04 18:15:42]

lgtm

[commit-bot: I haz the power, 2013-03-04 18:17:43]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jamesr@chromium.org/12385074/6

[commit-bot: I haz the power, 2013-03-04 20:35:50]

Change committed as 185963