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

ash/common/system/tray/tray_background_view.cc

 // Copyright (c) 2012 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/system/tray/tray_background_view.h"
 
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/shelf/shelf_constants.h"
 #include "ash/common/shelf/wm_shelf.h"
 #include "ash/common/shelf/wm_shelf_util.h"
@@ skipping 71 matching lines @@
   const static int kImageTypeDefault = 0;
   const static int kImageTypeOnBlack = 1;
   const static int kImageTypePressed = 2;
   const static int kNumStates = 3;
 
   const static int kImageHorizontal = 0;
   const static int kImageVertical = 1;
   const static int kNumOrientations = 2;
 
   explicit TrayBackground(TrayBackgroundView* tray_background_view)
-      : tray_background_view_(tray_background_view) {}
+      : tray_background_view_(tray_background_view), alpha_(0) {}
 
   ~TrayBackground() override {}
 
+  void set_alpha(int alpha) { alpha_ = alpha; }
+
  private:
   WmShelf* GetShelf() const { return tray_background_view_->shelf(); }
 
   void PaintMaterial(gfx::Canvas* canvas, views::View* view) const {
-    SkColor background_color = SK_ColorTRANSPARENT;
-    if (GetShelf()->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, alpha_));
     canvas->DrawRoundRect(view->GetLocalBounds(), kTrayRoundedBorderRadius,
                           background_paint);
 
     if (tray_background_view_->draw_background_as_active()) {
       SkPaint highlight_paint;
       highlight_paint.setFlags(SkPaint::kAntiAlias_Flag);
       highlight_paint.setColor(kShelfButtonActivatedHighlightColor);
       canvas->DrawRoundRect(view->GetLocalBounds(), kTrayRoundedBorderRadius,
                             highlight_paint);
     }
@@ skipping 36 matching lines @@
   void Paint(gfx::Canvas* canvas, views::View* view) const override {
     if (MaterialDesignController::IsShelfMaterial())
       PaintMaterial(canvas, view);
     else
       PaintNonMaterial(canvas, view);
   }
 
   // Reference to the TrayBackgroundView for which this is a background.
   TrayBackgroundView* tray_background_view_;
 
+  int alpha_;
+
   DISALLOW_COPY_AND_ASSIGN(TrayBackground);
 };
 
 TrayBackgroundView::TrayContainer::TrayContainer(ShelfAlignment alignment)
     : alignment_(alignment) {
   UpdateLayout();
 }
 
 void TrayBackgroundView::TrayContainer::SetAlignment(ShelfAlignment alignment) {
   if (alignment_ == alignment)
@@ skipping 174 matching lines @@
     if (event->type() == ui::ET_GESTURE_TAP_DOWN) {
       SetDrawBackgroundAsActive(true);
     } else if (event->type() == ui::ET_GESTURE_SCROLL_BEGIN ||
                event->type() == ui::ET_GESTURE_TAP_CANCEL) {
       SetDrawBackgroundAsActive(false);
     }
   }
   ActionableView::OnGestureEvent(event);
 }
 
-void TrayBackgroundView::UpdateBackground(int alpha) {
-  // The animator should never fire when the alternate shelf layout is used.
-  if (!background_ || draw_background_as_active_)
-    return;
-  SchedulePaint();
-}
-
 void TrayBackgroundView::SetContents(views::View* contents) {
   SetLayoutManager(new views::BoxLayout(views::BoxLayout::kVertical, 0, 0, 0));
   AddChildView(contents);
 }
 void TrayBackgroundView::SetContentsBackground() {
   background_ = new TrayBackground(this);
   tray_container_->set_background(background_);
 }
 
 void TrayBackgroundView::SetShelfAlignment(ShelfAlignment alignment) {
@@ skipping 124 matching lines @@
   if (!background_)
     return;
   SchedulePaint();
 }
 
 void TrayBackgroundView::UpdateBubbleViewArrow(
     views::TrayBubbleView* bubble_view) {
   // Nothing to do here.
 }
 
+void TrayBackgroundView::UpdateShelfItemBackground(int alpha) {
+  if (background_) {
+    background_->set_alpha(alpha);
+    SchedulePaint();
+  }
+}
+
 }  // namespace ash