cc: Remove all remaining use of WebCore Rect/Point/Size types from the compositor.

cc: Remove all remaining use of WebCore Rect/Point/Size types from the compositor. 

This change removes all IntPoint/FloatRect/IntSize/etc from the compositor. 
There remains an indirect dependency on these types through the 
WebCore::Region class, which we wrap but need to replace. However, the wrapper 
there hides the WebCore types inside it, so there are now no references to the 
types from anywhere else in the compositor. 

I went back and forth on how to deal with scroll "positions". The name suggested 
that they should be Points, and that the deltas should be Vectors. However this 
lent itself to super awkward math at times. In the end, it was much cleaner to 
make all scroll "positions" into scroll "offsets" and represent everything as 
Vectors. 

Covered by existing tests; no change in behaviour. 

R=enne 
BUG=147395
Relanding: https://codereview.chromium.org/11367080/

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=166027

[danakj, 2012-11-05 17:43:40]

going to reland this, i missed removing the stubs files from cc.gyp

[commit-bot: I haz the power, 2012-11-05 17:58:00]

No LGTM from a valid reviewer yet. Only full committers are accepted.
Even if an LGTM may have been provided, it was from a non-committer or
a lowly provisional committer, _not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[enne (OOO), 2012-11-05 18:02:58]

lgtm

[jamesr, 2012-11-05 18:02:59]

lgtm

[commit-bot: I haz the power, 2012-11-05 18:04:35]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/danakj@chromium.org/11366089/3001