tree 8ad47ff39c6e6c6e3201fababad8eaa3820154fc
parent 4f36274923812559cd9719083348de11daa9a3f2
author Hui Shu <hush@google.com> 1406828180 -0700
committer Bo Liu <boliu@google.com> 1406845597 -0700

Tile priority in Android WebView

Cherry pick of chromium r286731

Conflicts:
        cc/layers/picture_layer_impl_unittest.cc

Original Description:
Tiling priorities in Android Webview.

Use the parent compositor's clip and transform for tile
priorities in child compositor.

When the transform matrix changes in parent compositor
(hardware_renderer.cc), it posts the matrix and the clip to
the child compositor. (The parent clip is in screen space
and the parent matrix transforms from webview space to
screen space) Child compositor will use them for tile
prioritization.

In child compositor during updating tile priority, the clip
from parent is transformed from screen space to view space,
then from view space to content space. Then the result rect
will intersect with content_bounds() and the intersection
is used as tile priority input.

BUG:15771042
Change-Id: I3d1625f46649f032215810729d24717e5faceff7