mus: Server-side implementation of modal windows

components/mus/ws/event_dispatcher.cc

Index: components/mus/ws/event_dispatcher.cc
diff --git a/components/mus/ws/event_dispatcher.cc b/components/mus/ws/event_dispatcher.cc
index ead61660ad570645411ad7e55eec1f77a37ee403..55717b553d90406d7974344f06d079abc2a2f7a6 100644
--- a/components/mus/ws/event_dispatcher.cc
+++ b/components/mus/ws/event_dispatcher.cc
@@ -52,6 +52,16 @@ bool IsLocationInNonclientArea(const ServerWindow* target,
   return true;
 }
 
+ServerWindow* GetModalTargetForWindow(ServerWindow* target) {
+  for (ServerWindow* window = target; window; window = window->parent()) {
+    for (const auto& transient_child : window->transient_children()) {
+      if (transient_child->is_modal())
+        return GetModalTargetForWindow(transient_child);
+    }
+  }
+  return target;
+}
+
 }  // namespace
 
 class EventMatcher {
@@ -443,10 +453,12 @@ EventDispatcher::PointerTarget EventDispatcher::PointerTargetForEvent(
     const ui::PointerEvent& event) const {
   PointerTarget pointer_target;
   gfx::Point location(event.location());
-  pointer_target.window =
+  ServerWindow* target_window =
       FindDeepestVisibleWindowForEvents(root_, surface_id_, &location);
+  pointer_target.window = GetModalTargetForWindow(target_window);
   pointer_target.is_mouse_event = event.IsMousePointerEvent();
   pointer_target.in_nonclient_area =

[sky, 2016/03/02 18:28:33]

Aren't you going to use an enum to indicate modal?

[mohsen, 2016/03/03 22:54:59]

Not at the moment. That enum would be useful if we send it to the client (e.g.
the window manager). On the server side we only need to know who to send the
event to for which a boolean would be enough (maybe we need to rename it to
something better). For sending this information to the client, I've added a
paragraph and a comment to the design doc. Please take a look:
https://docs.google.com/document/d/1nrDrFEvXbGhqLvH4a1uutg3uFRJsNESZAUcAyYtQ6...

[sky, 2016/03/03 23:50:39]

If you don't send a flag indicating this, I'm not sure how happy some of the
code that the windowmanager usese will be if it sees events outside the bounds
of window. Did you make sure we ignore events outside the bounds of the window
in the clients?

[mohsen, 2016/03/04 16:24:17]

I've tested this code (using window_type_launcher) and it works properly (it
actually activates the modal window which is the desired behavior). The events
on the client side end up in Aura event dispatching code which I think handles
this case properly.

+      target_window != pointer_target.window ||
       IsLocationInNonclientArea(pointer_target.window, location);
   pointer_target.is_pointer_down = event.type() == ui::ET_POINTER_DOWN;
   return pointer_target;