Reland of "Apply Shelf/Dock opacity animations for the Material Design style."

ash/common/shelf/overflow_button.cc

 // 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.
 
 #include "ash/common/shelf/overflow_button.h"
 
 #include "ash/common/ash_constants.h"
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/shelf/ink_drop_button_listener.h"
 #include "ash/common/shelf/shelf_constants.h"
@@ skipping 13 matching lines @@
 #include "ui/gfx/transform.h"
 #include "ui/gfx/vector_icons_public.h"
 
 namespace ash {
 
 OverflowButton::OverflowButton(InkDropButtonListener* listener,
                                WmShelf* wm_shelf)
     : CustomButton(nullptr),
       bottom_image_(nullptr),
       listener_(listener),
-      wm_shelf_(wm_shelf) {
+      wm_shelf_(wm_shelf),
+      background_alpha_(0) {
   if (MaterialDesignController::IsShelfMaterial()) {
     bottom_image_md_ =
         CreateVectorIcon(gfx::VectorIconId::SHELF_OVERFLOW, kShelfIconColor);
     bottom_image_ = &bottom_image_md_;
   } else {
     bottom_image_ = ui::ResourceBundle::GetSharedInstance().GetImageSkiaNamed(
         IDR_ASH_SHELF_OVERFLOW);
   }
 
   SetFocusBehavior(FocusBehavior::ACCESSIBLE_ONLY);
   SetAccessibleName(l10n_util::GetStringUTF16(IDS_ASH_SHELF_OVERFLOW_NAME));
 }
 
 OverflowButton::~OverflowButton() {}
 
 void OverflowButton::OnShelfAlignmentChanged() {
   SchedulePaint();
 }
 
+void OverflowButton::SetBackgroundAlpha(int alpha) {
+  background_alpha_ = alpha;
+  SchedulePaint();
+}
+
 void OverflowButton::OnPaint(gfx::Canvas* canvas) {
   gfx::Rect bounds = CalculateButtonBounds();
   PaintBackground(canvas, bounds);
   PaintForeground(canvas, bounds);
 }
 
 void OverflowButton::NotifyClick(const ui::Event& event) {
   CustomButton::NotifyClick(event);
   if (listener_)
     listener_->ButtonPressed(this, event, ink_drop());
 }
 
 void OverflowButton::PaintBackground(gfx::Canvas* canvas,
                                      const gfx::Rect& bounds) {
   if (MaterialDesignController::IsShelfMaterial()) {
-    SkColor background_color = SK_ColorTRANSPARENT;
-    if (wm_shelf_->GetBackgroundType() ==
-        ShelfBackgroundType::SHELF_BACKGROUND_DEFAULT) {
-      background_color = SkColorSetA(kShelfBaseColor,
-                                     GetShelfConstant(SHELF_BACKGROUND_ALPHA));
-    }
-
-    // TODO(bruthig|tdanderson): The background should be changed using a
-    // fade in/out animation.
     SkPaint background_paint;
     background_paint.setFlags(SkPaint::kAntiAlias_Flag);
-    background_paint.setColor(background_color);
+    background_paint.setColor(SkColorSetA(kShelfBaseColor, background_alpha_));
     canvas->DrawRoundRect(bounds, kOverflowButtonCornerRadius,
                           background_paint);
 
     if (wm_shelf_->IsShowingOverflowBubble()) {
       SkPaint highlight_paint;
       highlight_paint.setFlags(SkPaint::kAntiAlias_Flag);
       highlight_paint.setColor(kShelfButtonActivatedHighlightColor);
       canvas->DrawRoundRect(bounds, kOverflowButtonCornerRadius,
                             highlight_paint);
     }
@@ skipping 73 matching lines @@
       bounds =
           gfx::Rect(bounds.x() + (bounds.width() - background->width()) / 2,
                     bounds.y() + kShelfItemInset, background->width(),
                     background->height());
     }
   }
   return bounds;
 }
 
 }  // namespace ash