Remove SerializedScriptValue special case from ShouldKeepAttributeAlive

Just noticed that this case is dead code;
there's only one readonly SerializedScriptValue attribute, but its getter
is custom, so this isn't relevant.

Source/core/frame/History.idl:
[Custom=Getter] readonly attribute SerializedScriptValue state;

R=haraken

Review URL: https://codereview.chromium.org/131053002

git-svn-id: svn://svn.chromium.org/blink/trunk@164754 bbb929c8-8fbe-4397-9dbb-9b2b20218538
RenderLayer and RenderLayerClipper should not be friends

This change moves backgroundClipRect and
parentClipRect to break the bad friendness.

BUG=307169

Review URL: https://codereview.chromium.org/126193002

git-svn-id: svn://svn.chromium.org/blink/trunk@164755 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add GCScope object to the oilpan heap infrastructure.

Sweep is still not implemented. Instead of actually sweeping we
clear all marks. Implementing actual sweeping is next on the list.

R=erik.corry@gmail.com, haraken@chromium.org, vegorov@chromium.org, wibling@chromium.org
BUG=

Review URL: https://codereview.chromium.org/128533002

git-svn-id: svn://svn.chromium.org/blink/trunk@164756 bbb929c8-8fbe-4397-9dbb-9b2b20218538