Support targeting for gestures in ViewTargeter

ui/views/view_targeter.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/views/view_targeter.h"
 
 #include "ui/events/event_target.h"
 #include "ui/views/focus/focus_manager.h"
 #include "ui/views/view.h"
 #include "ui/views/view_targeter_delegate.h"
@@ skipping 21 matching lines @@
   View* view = static_cast<View*>(root);
 
   if (event->IsKeyEvent())
     return FindTargetForKeyEvent(view, *static_cast<ui::KeyEvent*>(event));
 
   if (event->IsScrollEvent()) {
     return FindTargetForScrollEvent(view,
                                     *static_cast<ui::ScrollEvent*>(event));
   }
 
+  if (event->IsGestureEvent())
+    return FindTargetForGestureEvent(view, *(event->AsGestureEvent()));
+
   NOTREACHED() << "ViewTargeter does not yet support this event type.";
   return NULL;
 }
 
 ui::EventTarget* ViewTargeter::FindNextBestTarget(
     ui::EventTarget* previous_target,
     ui::Event* event) {
+  if (!previous_target)
+    return NULL;
+
+  if (event->IsGestureEvent()) {
+    return FindNextBestTargetForGestureEvent(previous_target,
+                                             *(event->AsGestureEvent()));
+  }
+
   return previous_target->GetParentTarget();
 }
 
 bool ViewTargeter::SubtreeCanAcceptEvent(
     ui::EventTarget* target,
     const ui::LocatedEvent& event) const {
   NOTREACHED();
   return false;
 }
 
 bool ViewTargeter::EventLocationInsideBounds(
     ui::EventTarget* target,
     const ui::LocatedEvent& event) const {
   NOTREACHED();
   return false;
 }
 
 View* ViewTargeter::FindTargetForKeyEvent(View* root, const ui::KeyEvent& key) {
   if (root->GetFocusManager())
     return root->GetFocusManager()->GetFocusedView();
   return NULL;
 }
 
 View* ViewTargeter::FindTargetForScrollEvent(View* root,
                                              const ui::ScrollEvent& scroll) {
   gfx::Rect rect(scroll.location(), gfx::Size(1, 1));
   return root->GetEffectiveViewTargeter()->TargetForRect(root, rect);
 }
 
+View* ViewTargeter::FindTargetForGestureEvent(View* root,
+                                              const ui::GestureEvent& gesture) {
+  NOTREACHED();

[tdanderson, 2014/08/26 20:21:15]

There are currently no call-sites that will hit this other than from in
EventProcessor, but that is done on the RootView's targeter. It was turning out
to be a bit of a mess to implement this as we had discussed on IM (using the
effective targeter of the parent) so I'm happy to leave this as NOTREACHED() for
now. We can discuss later about the best way to allow something to request
targeting for gestures at an arbitrary node in a View tree (or whether such a
thing should even be permitted).

[sadrul, 2014/08/27 22:49:54]

Add a TODO or a comment here as well, so that in case someone hits this, they
know we intend to fix this.

[tdanderson, 2014/08/27 23:25:57]

Done.

+  return NULL;
+}
+
+ui::EventTarget* ViewTargeter::FindNextBestTargetForGestureEvent(
+    ui::EventTarget* previous_target,
+    const ui::GestureEvent& gesture) {
+  NOTREACHED();
+  return NULL;
+}
+
 }  // namespace views