Fix flakiness in LayerTreeHostCacheBehaviorOnOutputSurfaceRecreated

We were relying on the ordering of WillBeginImplFrameOnThread and
DidInitializeCompositorFrameSink, which is not reliable as these calls
are async with regards to each other. This change switches to using
WillBeginImplFrameOnThread and DidInitializeRendererOnThread, which are
both compositor thread functions and will be ordered consistently.

CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel

Review-Url: https://codereview.chromium.org/2398283002
Cr-Commit-Position: refs/heads/master@{#423914}
1 file changed