commit 7be71c394259339472222de8297b4281c5c04bc7
author boliu@chromium.org <boliu@chromium.org@bbb929c8-8fbe-4397-9dbb-9b2b20218538> Tue Feb 18 22:07:33 2014 +0000
committer Bo Liu <boliu@google.com> Fri Mar 07 09:07:35 2014 -0800
tree d428934f7ba855e0c31973ad1fbb07bb30d2d8ee
parent fa88a35bc8f4a9e3504cb4da24c51f89a8482c96

Cherry-pick: Clear m_lastImageId for software compositor

Cherry-pick with conflict of
http://src.chromium.org/viewvc/blink?view=revision&revision=167365

Conflicts:
	Source/web/tests/Canvas2DLayerBridgeTest.cpp

Original description:

When android webview swith to software only mode, all mailboxes are
returned to Canvas2DLayerBridge. In this case, if the canvas is static,
then prepareMailbox will never return a new mailbox. So clear m_lastImageId
in this case.

BUG: 13328348

Change-Id: I5d8ec2cb5c613b0991bc66df29a0ff17441f018c