Page/layer flashes after GPU-accelerated CSS transition

Page/layer flashes after GPU-accelerated CSS transition
https://bugs.webkit.org/show_bug.cgi?id=72343

LayerRendererChromium was resizing the window to 1x1 at initialization.
In some cases, there is no drawLayers before switching back to
software rendering. This left the window resized to 1x1 and the
following software paints would therefore not be visible. This change
moves the reshape call into drawLayers so that it will only be called
if rendering will occur.

Patch by John Bates <jbates@google.com> on 2011-11-15
Reviewed by James Robinson.

New test: CCLayerTreeHostImplTest.reshapeNotCalledUntilDraw.

* platform/graphics/chromium/LayerRendererChromium.cpp:
(WebCore::LayerRendererChromium::viewportChanged):
(WebCore::LayerRendererChromium::doViewportChanged):
(WebCore::LayerRendererChromium::drawLayersInternal):
* platform/graphics/chromium/LayerRendererChromium.h:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@100340 268f45cc-cd09-0410-ab3c-d52691b4dbfc