Adding ripple effect for clicks on MD slider

ui/views/controls/slider.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 "ui/views/controls/slider.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 161 matching lines @@
 
 float Slider::GetAnimatingValue() const{
   return move_animation_.get() && move_animation_->is_animating()
              ? animating_value_
              : value_;
 }
 
 bool Slider::OnMousePressed(const ui::MouseEvent& event) {
   if (!event.IsOnlyLeftMouseButton())
     return false;
+  SetFocus(true);

[bruthig, 2016/09/21 00:27:46]

Instead of calling SetFocus() from OnMousePressed(), OnMouseReleased(),
OnGestureEvent(), I think you should move it to OnSliderDragStarted() and
OnSliderDragEnded().

[yiyix, 2016/09/21 15:20:52]

good call!!

   OnSliderDragStarted();
   PrepareForMove(event.location().x());
   MoveButtonTo(event.location());
   return true;
 }
 
 bool Slider::OnMouseDragged(const ui::MouseEvent& event) {
   MoveButtonTo(event.location());
   return true;
 }
 
 void Slider::OnMouseReleased(const ui::MouseEvent& event) {
+  SetFocus(false);
   OnSliderDragEnded();
 }
 
 bool Slider::OnKeyPressed(const ui::KeyEvent& event) {
   float new_value = value_;
   if (event.key_code() == ui::VKEY_LEFT)
     new_value -= keyboard_increment_;
   else if (event.key_code() == ui::VKEY_RIGHT)
     new_value += keyboard_increment_;
   else
     return false;
   SetValueInternal(new_value, VALUE_CHANGED_BY_USER);
   return true;
 }
 
 void Slider::OnFocus() {
   View::OnFocus();
+  SetFocus(true);
   SchedulePaint();
 }
 
 void Slider::OnBlur() {
   View::OnBlur();
+  SetFocus(false);
   SchedulePaint();
 }
 
 void Slider::OnGestureEvent(ui::GestureEvent* event) {
   switch (event->type()) {
     // In a multi point gesture only the touch point will generate
     // an ET_GESTURE_TAP_DOWN event.
     case ui::ET_GESTURE_TAP_DOWN:
       OnSliderDragStarted();
       PrepareForMove(event->location().x());
       // Intentional fall through to next case.
     case ui::ET_GESTURE_SCROLL_BEGIN:
     case ui::ET_GESTURE_SCROLL_UPDATE:
+      SetFocus(true);
       MoveButtonTo(event->location());
       event->SetHandled();
       break;
     case ui::ET_GESTURE_END:
+      SetFocus(false);
       MoveButtonTo(event->location());
       event->SetHandled();
       if (event->details().touch_points() <= 1)
         OnSliderDragEnded();
       break;
     default:
       break;
   }
 }
 
 void Slider::AnimationProgressed(const gfx::Animation* animation) {
   animating_value_ = animation->CurrentValueBetween(animating_value_, value_);

[bruthig, 2016/09/21 00:27:46]

This should only update |animating_value_| if |animation| == |move_animation_|. 
And it should only call SchedulePaint() when |animating_value_| is updated.

[yiyix, 2016/09/21 15:20:52]

Done.

   SchedulePaint();
 }
 
 void Slider::GetAccessibleState(ui::AXViewState* state) {
   state->role = ui::AX_ROLE_SLIDER;
   state->name = accessible_name_;
   state->value = base::UTF8ToUTF16(
       base::StringPrintf("%d%%", static_cast<int>(value_ * 100 + 0.5)));
 }
 
 void Slider::OnSliderDragStarted() {
   if (listener_)
     listener_->SliderDragStarted(this);
 }
 
 void Slider::OnSliderDragEnded() {
   if (listener_)
     listener_->SliderDragEnded(this);
 }
 
 }  // namespace views