Update WM shadows for MD.

ui/wm/core/shadow.h

Index: ui/wm/core/shadow.h
diff --git a/ui/wm/core/shadow.h b/ui/wm/core/shadow.h
index 81199f848fd361d94cbc7ac006e66935f0f8ec22..07df0235e5731e3df72c5c9a99e64380e0458527 100644
--- a/ui/wm/core/shadow.h
+++ b/ui/wm/core/shadow.h
@@ -69,6 +69,10 @@ class WM_EXPORT Shadow : public ui::ImplicitAnimationObserver {
   // |content_bounds_|.
   void UpdateLayerBounds();
 
+  // Returns the "elevation" for |style_|, which dictates the shadow's display
+  // characteristics.

[James Cook, 2016/12/05 23:38:35]

nit: Document that elevation currently means size of shadow in pixels, or at
least that shadow size is directly proportional to elevation. I think it's
important that elevation isn't just 1,2,3

[Evan Stade, 2016/12/06 00:53:21]

Done.

+  int ElevationForStyle();
+
   // The current style, set when the transition animation starts.
   Style style_;
 
@@ -79,16 +83,9 @@ class WM_EXPORT Shadow : public ui::ImplicitAnimationObserver {
   // The actual shadow layer corresponding to a cc::NinePatchLayer.
   std::unique_ptr<ui::Layer> shadow_layer_;
 
-  // Size of the current shadow image.
-  gfx::Size image_size_;
-
   // Bounds of the content that the shadow encloses.
   gfx::Rect content_bounds_;
 
-  // The interior inset of the shadow images. The content bounds of the image
-  // grid should be set to |content_bounds_| inset by this amount.
-  int interior_inset_;
-
   DISALLOW_COPY_AND_ASSIGN(Shadow);
 };