[ash-md] Fades overview header in and out

ash/common/wm/overview/scoped_transform_overview_window.h

Index: ash/common/wm/overview/scoped_transform_overview_window.h
diff --git a/ash/common/wm/overview/scoped_transform_overview_window.h b/ash/common/wm/overview/scoped_transform_overview_window.h
index 11b50ef1c146b9bc6358793687b1e6085d90749c..f6aee5e3b040b812b22ec38fc0b84d414da7ff40 100644
--- a/ash/common/wm/overview/scoped_transform_overview_window.h
+++ b/ash/common/wm/overview/scoped_transform_overview_window.h
@@ -12,6 +12,7 @@
 #include "ash/common/wm/overview/overview_animation_type.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
+#include "third_party/skia/include/core/SkColor.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/gfx/transform.h"
 
@@ -32,6 +33,7 @@ class WmWindow;
 // object.
 class ASH_EXPORT ScopedTransformOverviewWindow {
  public:
+  class OverviewContentMask;
   using ScopedAnimationSettings =
       std::vector<std::unique_ptr<ScopedOverviewAnimationSettings>>;
 
@@ -97,6 +99,10 @@ class ASH_EXPORT ScopedTransformOverviewWindow {
   // header to be hidden.
   gfx::Rect GetTransformedBounds(bool hide_header) const;
 
+  // Returns TOP_VIEW_COLOR property of |window_| unless there are transient
+  // ancestors in which case returns SK_ColorTRANSPARENT.
+  SkColor GetTopColor() const;
+
   // Returns TOP_VIEW_INSET property of |window_| unless there are transient
   // ancestors in which case returns 0.
   int GetTopInset() const;
@@ -116,20 +122,24 @@ class ASH_EXPORT ScopedTransformOverviewWindow {
   void PrepareForOverview();
 
   // Applies the |transform| to the overview window and all of its transient
-  // children. With Material Design creates a mask layer with the bottom edge
-  // using rounded corners of |radius|. When |use_mask| is set, hides the
-  // original window header and uses rounded rectangle mask which may be
-  // resource-intensive. When |use_shape| is set and |use_mask| is not, uses
-  // SetAlphaShape to mask the header.
+  // children.
   void SetTransform(WmWindow* root_window,
                     const gfx::Transform& transform,
-                    bool use_mask,
-                    bool use_shape,
-                    float radius);
+                    bool use_mask);
 
   // Set's the opacity of the managed windows.
   void SetOpacity(float opacity);
 
+  // Creates a mask layer with the bottom edge using rounded corners of
+  // |radius|. When |use_mask| is set, hides the original window header and uses
+  // rounded rectangle mask which may be resource-intensive. When |use_shape| is
+  // set and |use_mask| is not, uses SetAlphaShape to mask the header.
+  void HideHeaderAndSetShape(bool use_mask, bool use_shape, int radius);
+
+  // Restores original window shape and removes the mask if installed. Safe to
+  // call even if HideHeaderAndSetShape() has not been called.
+  void ShowHeaderAndResetShape();
+
   WmWindow* window() const { return window_; }
 
   // Closes the transient root of the window managed by |this|.
@@ -137,7 +147,6 @@ class ASH_EXPORT ScopedTransformOverviewWindow {
 
  private:
   friend class WindowSelectorTest;
-  class OverviewContentMask;
 
   enum OriginalVisibility {
     ORIGINALLY_VISIBLE,