Merge 112436 - [chromium] layer->clipRect() is not initialized for layers that create a renderSurfa…

Merge 112436 - [chromium] layer->clipRect() is not initialized for layers that create a renderSurface.
https://bugs.webkit.org/show_bug.cgi?id=74147

Reviewed by Adrienne Walker.

Source/WebCore:

Added 3 additional unit tests; Modified existing unit tests and layout tests.

The layer's clipRect and usesLayerClipping information was not
being initialized for layers that created a renderSurface. (It
was, however, being initialized for the renderSurface itself.)
This patch adds a unit test that reproduces that this is an error,
other unit tests to tightly test the value of clipRect being
initialized, and adds the logic to properly initialize the
clipRect.

Before this patch, this bug was causing flashing on tab-switch on
the apple iphone page. Even worse, with partial swap enabled, the
layers would simply disappear, because the first frame the
clipRect is uninitialized and the layer is not drawn, and the
second frame onwards, the damage tracker correctly things nothing
is damaged, so it doesn't draw that layer again until other damage
causes it to be redrawn.

* platform/graphics/chromium/cc/CCLayerTreeHostCommon.cpp:
(WebCore::calculateDrawTransformsAndVisibilityInternal):

Source/WebKit/chromium:

Added 3 more unit tests. One reproduces the clipRect problem in an
integrated manner, the other two directly test that clipRects are
properly initialized.

* tests/CCLayerTreeHostCommonTest.cpp:
(WebCore::TEST):
(WebCore):
* tests/CCLayerTreeTestCommon.h:
(WebKitTests):

LayoutTests:

* platform/chromium/test_expectations.txt: marked test as needing rebaselining

TBR=shawnsingh@chromium.org
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=112702