Add MD ink drop ripple to app list button

ash/shelf/shelf_button.cc

Index: ash/shelf/shelf_button.cc
diff --git a/ash/shelf/shelf_button.cc b/ash/shelf/shelf_button.cc
index 11707490b46bdc274fc6ef40d4250cd87fa589df..1336d34d75c2d4053d2f2cfb9019df16a66c8413 100644
--- a/ash/shelf/shelf_button.cc
+++ b/ash/shelf/shelf_button.cc
@@ -54,7 +54,6 @@ const int kIndicatorCanvasScale = 5;
 const int kInkDropSmallSize = 48;
 const int kInkDropLargeSize = 60;
 const int kInkDropLargeCornerRadius = 4;
-const SkColor kInkDropBaseColor = SK_ColorWHITE;
 
 // Paints an activity indicator on |canvas| whose |size| is specified in DIP.
 void PaintIndicatorOnCanvas(gfx::Canvas* canvas, const gfx::Size& size) {
@@ -261,7 +260,7 @@ ShelfButton::ShelfButton(InkDropButtonListener* listener, ShelfView* shelf_view)
   SetFocusBehavior(FocusBehavior::ACCESSIBLE_ONLY);
   if (ash::MaterialDesignController::IsShelfMaterial()) {
     SetHasInkDrop(true);
-    set_ink_drop_base_color(kInkDropBaseColor);
+    set_ink_drop_base_color(kShelfInkDropBaseColor);
     set_ink_drop_visible_opacity(kShelfInkDropVisibleOpacity);
   }