Reland of [ash-md] Fades overview header in and out

ash/common/wm/overview/scoped_transform_overview_window.h

 // Copyright 2013 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 ASH_COMMON_WM_OVERVIEW_SCOPED_TRANSFORM_OVERVIEW_WINDOW_H_
 #define ASH_COMMON_WM_OVERVIEW_SCOPED_TRANSFORM_OVERVIEW_WINDOW_H_
 
 #include <memory>
 #include <vector>
 
 #include "ash/ash_export.h"
 #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"
 
 class SkRegion;
 
 namespace gfx {
 class Rect;
 }
 
 namespace ash {
 
 class ScopedOverviewAnimationSettings;
 class WmWindow;
 
 // Manages a window, and it's transient children, in the overview mode. This
 // class allows transforming the windows with a helper to determine the best
 // fit in certain bounds. The window's state is restored on destruction of this
 // object.
 class ASH_EXPORT ScopedTransformOverviewWindow {
  public:
+  class OverviewContentMask;
   using ScopedAnimationSettings =
       std::vector<std::unique_ptr<ScopedOverviewAnimationSettings>>;
 
   // Calculates and returns an optimal scale ratio. With MD this is only
   // taking into account |size.height()| as the width can vary. Without MD this
   // returns the scale that allows the item to fully fit within |size|.
   static float GetItemScale(const gfx::Size& source,
                             const gfx::Size& target,
                             int top_view_inset,
                             int title_height);
@@ skipping 45 matching lines @@
   gfx::Rect GetTargetBoundsInScreen() const;
 
   // Calculates the bounds of a |window_| after being transformed to the
   // selector's space. With Material Design those bounds are a union of all
   // regular (normal and panel) windows in the |window_|'s transient hierarchy.
   // The returned Rect is in virtual screen coordinates. When |hide_header| is
   // true the returned bounds are adjusted to allow the original |window_|'s
   // 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;
 
   // Restores and animates the managed window to it's non overview mode state.
   void RestoreWindow();
 
   // Forces the managed window to be shown (ie not hidden or minimized) when
   // calling RestoreWindow().
   void ShowWindowOnExit();
 
   // Informs the ScopedTransformOverviewWindow that the window being watched was
   // destroyed. This resets the internal window pointer.
   void OnWindowDestroyed();
 
   // Prepares for overview mode by doing any necessary actions before entering.
   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|.
   void Close();
 
  private:
   friend class WindowSelectorTest;
-  class OverviewContentMask;
 
   enum OriginalVisibility {
     ORIGINALLY_VISIBLE,
     ORIGINALLY_MINIMIZED,
     ORIGINALLY_DOCKED_MINIMIZED,
   };
 
   // Shows the window if it was minimized.
   void ShowWindowIfMinimized();
 
@@ skipping 37 matching lines @@
   float original_opacity_;
 
   base::WeakPtrFactory<ScopedTransformOverviewWindow> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedTransformOverviewWindow);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_WM_OVERVIEW_SCOPED_TRANSFORM_OVERVIEW_WINDOW_H_