Transparency support in Windows
* Added DWMExtendFromIntoClientArea on composition changes
* Added maximize support for transparent (WS_POPUP) type windows
Transparency support in Mac OS X
Fix crashing in Snow Leopard due to race condition.
Merge branch 'transparency' into node

Conflicts:
	content/browser/renderer_host/compositing_iosurface_mac.mm
	ui/views/win/hwnd_message_handler.cc
Fixes for embed protocol