Support targeting for gestures in ViewTargeter

ui/views/view_targeter.cc

Index: ui/views/view_targeter.cc
diff --git a/ui/views/view_targeter.cc b/ui/views/view_targeter.cc
index 99c28fe78755440bd24d4d3b046198fab9a6d212..f895ddb16927391e73e7a818493c6837edfc1285 100644
--- a/ui/views/view_targeter.cc
+++ b/ui/views/view_targeter.cc
@@ -39,6 +39,9 @@ ui::EventTarget* ViewTargeter::FindTargetForEvent(ui::EventTarget* root,
                                     *static_cast<ui::ScrollEvent*>(event));
   }
 
+  if (event->IsGestureEvent())
+    return FindTargetForGestureEvent(view, *(event->AsGestureEvent()));
+
   NOTREACHED() << "ViewTargeter does not yet support this event type.";
   return NULL;
 }
@@ -46,6 +49,14 @@ ui::EventTarget* ViewTargeter::FindTargetForEvent(ui::EventTarget* root,
 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();
 }
 
@@ -75,4 +86,17 @@ View* ViewTargeter::FindTargetForScrollEvent(View* root,
   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