[ash-md] Animates ToggleButton highlight to move it in sync with the thumb

ui/views/controls/button/toggle_button.cc

 // Copyright 2016 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 "ui/views/controls/button/toggle_button.h"
 
 #include "third_party/skia/include/core/SkDrawLooper.h"
 #include "third_party/skia/include/core/SkPaint.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/color_palette.h"
@@ skipping 81 matching lines @@
   thumb_paint.setStyle(SkPaint::kFill_Style);
   thumb_paint.setAntiAlias(true);
   const SkColor thumb_on_color = GetNativeTheme()->GetSystemColor(
       ui::NativeTheme::kColorId_ProminentButtonColor);
   // TODO(estade): get this color from the theme?
   const SkColor thumb_off_color = SK_ColorWHITE;
   thumb_paint.setColor(
       color_utils::AlphaBlend(thumb_on_color, thumb_off_color, blend));
   canvas->DrawCircle(gfx::RectF(thumb_bounds).CenterPoint(),
                      thumb_bounds.height() / 2.f, thumb_paint);
+
+  // Adjust thumb ink drop highlight position to make it animate with the thumb.
+  OffsetInkDropRipple(thumb_bounds.CenterPoint() - original_center_point_);

[Evan Stade, 2016/10/10 17:33:15]

I'm kind of skeptical this will look great/stay in sync at a per-frame level. I
think instead we should have the thumb be a separate View and AddInkDropLayer
makes the ink drop layer a child of that view's layer.

[varkha, 2016/10/12 00:44:59]

Done.

 }
 
 void ToggleButton::NotifyClick(const ui::Event& event) {
   SetIsOn(!is_on(), true);
   CustomButton::NotifyClick(event);
 }
 
 void ToggleButton::OnNativeThemeChanged(const ui::NativeTheme* theme) {
   SchedulePaint();
 }
 
+void ToggleButton::AddInkDropLayer(ui::Layer* ink_drop_layer) {
+  original_center_point_ = GetThumbBounds().CenterPoint();
+  CustomButton::AddInkDropLayer(ink_drop_layer);
+}
+
 std::unique_ptr<InkDropRipple> ToggleButton::CreateInkDropRipple() const {
   return CreateDefaultInkDropRipple(GetThumbBounds().CenterPoint());
 }
 
 SkColor ToggleButton::GetInkDropBaseColor() const {
   return is_on()
              ? GetNativeTheme()->GetSystemColor(
                    ui::NativeTheme::kColorId_ProminentButtonColor)
              : kTrackOffColor;
 }
@@ skipping 15 matching lines @@
   thumb_bounds.set_x(thumb_bounds.x() +
                      slide_animation_.GetCurrentValue() *
                          (thumb_bounds.width() - thumb_bounds.height()));
   // The thumb is a circle, so the width should match the height.
   thumb_bounds.set_width(thumb_bounds.height());
   thumb_bounds.set_x(GetMirroredXForRect(thumb_bounds));
   return thumb_bounds;
 }
 
 }  // namespace views