Desktop Aura: Allow tab drags out of window.

You can now drag tabs in and out of windows in linux_aura builds. This patch has a lot of moving parts and caveats though.

Moving parts in the patch:
- Added system location to aura::Events.
- Forwarding move events from RootWindowHostLinux to the TabDragController through an observer.
- MessagePumpAuraX11 now can block waiting for a window to be mapped. If we don't do this, we can't perform a grab on the new window.
- The drag offset is threaded from TabDragController through the WindowMoveController interface. (There's no other non-racey way of getting this data locally from X.)
- RootWindowHostLinux now has working Show()/Hide().

TODOs:
- After releasing a new window, the window looks focused, but isn't. You have to click on it for it to receive input focus.

BUG=133059
TEST=none

Review URL: https://chromiumcodereview.appspot.com/10828133

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@152180 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 3 insertions, 0 deletions

diff --git a/ui/aura/root_window_host.h b/ui/aura/root_window_host.h
index 65a3f19..74502bf 100644
--- a/ui/aura/root_window_host.h
+++ b/ui/aura/root_window_host.h
@@ -50,6 +50,9 @@ class RootWindowHost {
   // Shows the RootWindowHost.
   virtual void Show() = 0;
 
+  // Hides the RootWindowHost.
+  virtual void Hide() = 0;
+
   // Toggles the host's full screen state.
   virtual void ToggleFullScreen() = 0;