cc: Fix impl-side painting rasterization at >1 contents scales

cc: Fix impl-side painting rasterization at >1 contents scales

Previously there was a content space vs. layer space mixup.  cc::Tile had a
member variable that was labeled rect_in_layer_space, but the tilings were
making a content space rect.  It's actually impossible to have an int rect in
layer space for most content spaces, so this got renamed to just be
content_space rect.

The actual bug was that this rect was being used to check if a given picture's
layer rect intersected it, so as soon as you got over bounds() / content_scale
away from the origin, the tile was getting nothing rastered to it and whatever
memory was in the canvas was being used, which happened to be old tiles.

R=aelias@chromium.org
BUG=164750
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=171964

[nduca, 2012-12-08 00:55:45]

omg lgtm

[aelias_OOO_until_Jul13, 2012-12-08 01:14:55]

lgtm

[commit-bot: I haz the power, 2012-12-08 01:37:05]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/enne@chromium.org/11466032/1

[commit-bot: I haz the power, 2012-12-08 08:48:22]

Change committed as 171964