Add ink drop ripple to status tray

ash/common/system/tray/tray_background_view.h

Index: ash/common/system/tray/tray_background_view.h
diff --git a/ash/common/system/tray/tray_background_view.h b/ash/common/system/tray/tray_background_view.h
index 4a72dda62f34765ed11392e2b5292618367841dd..58f84dffa562e8711a6e5554cdc4317df78d34ee 100644
--- a/ash/common/system/tray/tray_background_view.h
+++ b/ash/common/system/tray/tray_background_view.h
@@ -13,6 +13,7 @@
 #include "ash/public/cpp/shelf_types.h"
 #include "base/macros.h"
 #include "ui/compositor/layer_animation_observer.h"
+#include "ui/gfx/geometry/insets.h"
 #include "ui/views/bubble/tray_bubble_view.h"
 
 namespace ash {
@@ -158,6 +159,13 @@ class ASH_EXPORT TrayBackgroundView : public ActionableView,
   // SetVisible(false) is called.
   void HideTransformation();
 
+  // Helper function that returns background insets relative to local bounds.
+  gfx::Insets GetBackgroundInsets() const;
+
+  // Helper function that calculates background bounds relative to local bounds
+  // based on the background insets returned from GetBackgroundInsets().
+  gfx::Rect GetBackgroundBounds() const;

[bruthig, 2016/11/17 21:48:01]

With the name 'GetBackgroundBounds()' I would expect this to be used by
PaintMaterial() and for the creation of the InkDropMask, but
'GetBackgroundBounds()' is adding some extra padding to work around dynamically
resizing hosts and shouldn't be used in these places. So I still think this
would be better named as GetInkDropBounds()

[mohsen, 2016/11/18 05:20:56]

Right. Done.

+
   // The shelf containing the system tray for this view.
   WmShelf* wm_shelf_;