Add MD ink drop ripple to app list button

ui/views/animation/ink_drop_host_view.h

 // Copyright 2016 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.
 
 #ifndef UI_VIEWS_ANIMATION_INK_DROP_HOST_VIEW_H_
 #define UI_VIEWS_ANIMATION_INK_DROP_HOST_VIEW_H_
 
 #include <memory>
 
 #include "third_party/skia/include/core/SkColor.h"
@@ skipping 68 matching lines @@
   // Should return true if the ink drop is also used to depict focus.
   virtual bool ShouldShowInkDropForFocus() const;
 
   InkDrop* ink_drop() { return ink_drop_.get(); }
 
   // Toggle to enable/disable an InkDrop on this View.  Descendants can override
   // CreateInkDropHighlight() and CreateInkDropRipple() to change the look/feel
   // of the InkDrop.
   void SetHasInkDrop(bool has_an_ink_drop);
 
+  // An overload of SetHasInkDrop() that takes an extra argument specifying
+  // whether the default gesture handler should be installed for the ink drop or
+  // not. |handles_gesture_event| can only be true when |has_ink_drop| is true.
+  void SetHasInkDrop(bool has_an_ink_drop, bool handles_gesture_event);

[James Cook, 2016/06/23 20:08:08]

Having a method that takes two bools side by side, and only allows 3 states, is
confusing, especially when you already have a single-bool version. I would
prefer that you declare an enum for the 3 states and collapse the two methods
into one like SetHasInkDrop(InkDrop state).

Alternately you could have two methods, SetHasInkDrop() and
SetHandlesGestureEvents().

[mohsen, 2016/06/27 22:17:10]

Right. I believe having two separate methods would also be confusing as one is
only meaningful if the other is set to true. It is also hard to manage
especially if they can be called in any order. Switched to using a 3-valued
enum.

+
  private:
   class InkDropGestureHandler;
   friend class InkDropGestureHandler;
   friend class test::InkDropHostViewTestApi;
 
   // The last user Event to trigger an ink drop ripple animation.
   std::unique_ptr<ui::LocatedEvent> last_ripple_triggering_event_;
 
   std::unique_ptr<InkDrop> ink_drop_;
 
   // Intentionally declared after |ink_drop_| so that it doesn't access a
   // destroyed |ink_drop_| during destruction.
   std::unique_ptr<InkDropGestureHandler> gesture_handler_;
 
   gfx::Size ink_drop_size_;
 
   float ink_drop_visible_opacity_;
 
   // Determines whether the view was already painting to layer before adding ink
   // drop layer.
   bool old_paint_to_layer_;
 
   bool destroying_;
 
   DISALLOW_COPY_AND_ASSIGN(InkDropHostView);
 };
 }  // namespace views
 
 #endif  // UI_VIEWS_ANIMATION_INK_DROP_HOST_VIEW_H_