Fix handling of Mac accelerated plugin layers across tab switch.

Fix handling of Mac accelerated plugin layers across tab switch.

A few related changes to make tab switching work with accelerated plugins:
- Re-attach our layer to the view layer whenever it changes; using setWantsLayer: creates a layer that AppKit manages at will, so we can't rely on it.
- Override setFrame: on our layer to ignore bogus values sent by the view's layer.
- Notify the accelerated surface when our parent (and thus drawing context) changes, so it can associate its texture with the new context.

BUG=37701
TEST=Load the pepper test plugin (or a CA plugin in a build with CA enabled) and switch tabs away and back. The plugin should still be visible.

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=42273

[Ken Russell (switch to Gerrit), 2010-03-22 20:52:26]

LGTM. Thanks for fixing this.

[pink (ping after 24hrs), 2010-03-23 17:32:04]

nit

http://codereview.chromium.org/1166002/diff/1/7
File chrome/browser/renderer_host/render_widget_host_view_mac.mm (right):

http://codereview.chromium.org/1166002/diff/1/7#newcode1676
chrome/browser/renderer_host/render_widget_host_view_mac.mm:1676:
AcceleratedPluginLayer* plugin_layer = [[AcceleratedPluginLayer alloc]
objC should use objC naming: pluginLayer, etc.