scopingNodeFor should not use null for document scope.

If scopingNodeFor returns null, we should skip the CSSStyleSheet.

BUG=320929,321495

Review URL: https://codereview.chromium.org/76123002

git-svn-id: svn://svn.chromium.org/blink/trunk@162437 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove unnecessary static_casts to AsyncFileSystemCallbacks.

The specified objects are instances of derived classes of
AsyncFileSystemCallbacks, and PassRefPtr<> is clever enough to handle
inheritance.

BUG=none

Review URL: https://codereview.chromium.org/80113002

git-svn-id: svn://svn.chromium.org/blink/trunk@162438 bbb929c8-8fbe-4397-9dbb-9b2b20218538
StyleEngine: Encapsulate dirty scope tracking

This change extracts StyleTreeScopeTracker from StyleEngine.
The class encapsulates the special-case handling for
document scope to improve readability on StyleEngine side.

BUG=none
R=esprehn, tasak, dglazkov
TEST=none

Review URL: https://codereview.chromium.org/77963003

git-svn-id: svn://svn.chromium.org/blink/trunk@162439 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add TransformOperation(s)::dependsOnBoxSize and make apply return void

This patch adds a dependsOnBoxSize function to TransformOperation(s),
pulling the logic out of the apply functions.

Offloading layout-sensitive converted operations to the compositor can 
cause bugs and we don't like bugs. This patch helps us detect these 
cases.

R=shans,dstockwell
BUG=321840

Review URL: https://codereview.chromium.org/80093002

git-svn-id: svn://svn.chromium.org/blink/trunk@162440 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Web Animations CSS: Simplify interaction between CompositorAnimations and KeyframeAnimationEffect

This patch implements some methods in KeyframeAnimationEffect that gives CompositorAnimations direct access to things like the set of properties an animation controls. It reduces the surface area of CompositorAnimationsKeyframeEffectHelper to one method.

I suspect we might be able to remove this method too in a future patch.

Review URL: https://codereview.chromium.org/74883002

git-svn-id: svn://svn.chromium.org/blink/trunk@162441 bbb929c8-8fbe-4397-9dbb-9b2b20218538