Create an interface WindowEventTarget to enable a class to receive
Windows input events.

This interface is defined in the newly added ui\base\window_event_target.cc/.h files.

It is implemented by the HWNDMessageHandler class. The class sets the interface as
window property on the HWND. The LegacyRenderWidgetHostHWND class retrieves this interface
via the window property and invokes the corresponding methods.

This is much cleaner than the current method of forwarding input messages from the
LegacyRenderWidgetHostHWND class via SendMessage and also avoids mucking with the
WPARAM of WM_MOUSEMOVE messages to ensure that the parent does not track those messages.

BUG=342323
R=sky@chromium.org
TBR=cpu

Review URL: https://codereview.chromium.org/165753002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252365 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252365
Add bool variables to name the enable_pixel_output param in tests.

These two tests don't give the boolean literal a name. They should.
The Vsync test used to claim to want pixel output but the test
passes without it, so leave pixel output disabled. For the ozone
software output device tests, only set enable_pixel_output true for
the test that compares the pixel output, though this flag is
meaningless for software compositing right now.

BUG=270918
R=dnicoara@chromium.org

Review URL: https://codereview.chromium.org/173933002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252366 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252366