GitLab

Move it to be non-virtual methods on SingleThreadProxy and ThreadProxy.
LayerTreeHost only needs to call it on the SingleThreadProxy, and make
it do that before calling Composite() instead of having Composite()
early out.

Merge LTH::InitializeOutputSurfaceIfNeeded into LTH::Composite.

NOTRY=true
R=enne
BUG=374287

Review URL: https://codereview.chromium.org/286293002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@271769 0039d316-1c4b-4281-b951-d872f2087c98