Revert of Simplify the logic in DesktopWindowTreeHostX11 for FocusOut...

Revert of Simplify the logic in DesktopWindowTreeHostX11 for FocusOut (https://codereview.chromium.org/379773003/)

Reason for revert:
I am reverting this CL because it causes regressions like crbug.com/395985. This CL is in the right direction, but I need to make the capture code for tab dragging less crazy first. See comment #3 in crbug.com/395985 for more details

Original issue's description:
> Simplify the logic in DesktopWindowTreeHostX11 for FocusOut
> 
> We should have the same handling regardless of whether the 'mode' member is
> NotifyGrab or NotifyUngrab. According to
> http://tronche.com/gui/x/xlib/events/input-focus/grab.html, whether the mode
> field is NotifyGrab or NotifyUngrab depends on whether there is a new
> capturer for the keyboard. The X window has lost keyboard capture in both cases.
> 
> BUG=392480
> TEST=None
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=283823

TBR=erg@chromium.org,erg@google.com,sadrul@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=392480

Review URL: https://codereview.chromium.org/409223003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@284919 0039d316-1c4b-4281-b951-d872f2087c98

ui/aura/window_event_dispatcher.cc

@@ -201,6 +201,11 @@ gfx::Point WindowEventDispatcher::GetLastMouseLocationInRoot() const {
   return location;
 }
 
+void WindowEventDispatcher::OnHostLostMouseGrab() {
+  mouse_pressed_handler_ = NULL;
+  mouse_moved_handler_ = NULL;
+}
+
 void WindowEventDispatcher::OnCursorMovedToRootLocation(
     const gfx::Point& root_location) {
   SetLastMouseLocation(window(), root_location);

ui/aura/window_event_dispatcher.h

@@ -107,6 +107,7 @@ class AURA_EXPORT WindowEventDispatcher : public ui::EventProcessor,
   // coordinates. This may return a point outside the root window's bounds.
   gfx::Point GetLastMouseLocationInRoot() const;
 
+  void OnHostLostMouseGrab();
   void OnCursorMovedToRootLocation(const gfx::Point& root_location);
 
   // TODO(beng): This is only needed because this cleanup needs to happen after

ui/aura/window_tree_host_x11.cc

@@ -416,6 +416,7 @@ uint32_t WindowTreeHostX11::DispatchEvent(const ui::PlatformEvent& event) {
       break;
     }
     case FocusOut:
+      if (xev->xfocus.mode != NotifyGrab)
         OnHostLostWindowCapture();
       break;
     case ConfigureNotify: {

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc

@@ -1618,8 +1618,13 @@ uint32_t DesktopWindowTreeHostX11::DispatchEvent(
       break;
     }
     case FocusOut:
+      if (xev->xfocus.mode != NotifyGrab) {
         ReleaseCapture();
+        OnHostLostWindowCapture();
         X11DesktopHandler::get()->ProcessXEvent(xev);
+      } else {
+        dispatcher()->OnHostLostMouseGrab();
+      }
       break;
     case FocusIn:
       X11DesktopHandler::get()->ProcessXEvent(xev);