Make views Slider accessible on Chrome OS

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 "base/logging.h"
 #include "base/message_loop.h"
+#include "base/stringprintf.h"
+#include "base/utf_string_conversions.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "third_party/skia/include/core/SkPaint.h"
+#include "ui/base/accessibility/accessible_view_state.h"
 #include "ui/base/animation/slide_animation.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/point.h"
 #include "ui/gfx/rect.h"
+#include "ui/views/widget/widget.h"
 
 namespace {
 const int kSlideValueChangeDurationMS = 150;
 }
 
 namespace views {
 
 Slider::Slider(SliderListener* listener, Orientation orientation)
     : listener_(listener),
       orientation_(orientation),
@@ skipping 29 matching lines @@
     // Do not animate when setting the value of the slider for the first time.
     // There is no message-loop when running tests. So we cannot animate then.
     animating_value_ = old_value;
     move_animation_.reset(new ui::SlideAnimation(this));
     move_animation_->SetSlideDuration(kSlideValueChangeDurationMS);
     move_animation_->Show();
     AnimationProgressed(move_animation_.get());
   } else {
     SchedulePaint();
   }
+  if (GetWidget()) {
+    GetWidget()->NotifyAccessibilityEvent(
+        this, ui::AccessibilityTypes::EVENT_VALUE_CHANGED, true);
+  }
+}
+
+void Slider::SetAccessibleName(const string16& name) {
+  accessible_name_ = name;
 }
 
 gfx::Size Slider::GetPreferredSize() {
   const int kSizeMajor = 200;
   const int kSizeMinor = 40;
 
   if (orientation_ == HORIZONTAL)
     return gfx::Size(kSizeMajor, kSizeMinor);
   return gfx::Size(kSizeMinor, kSizeMajor);
 }
@@ skipping 65 matching lines @@
                      VALUE_CHANGED_BY_USER);
   }
   return true;
 }
 
 void Slider::AnimationProgressed(const ui::Animation* animation) {
   animating_value_ = animation->CurrentValueBetween(animating_value_, value_);
   SchedulePaint();
 }
 
+void Slider::GetAccessibleState(ui::AccessibleViewState* state) {
+  state->role = ui::AccessibilityTypes::ROLE_SLIDER;
+  state->name = accessible_name_;
+  state->value = UTF8ToUTF16(
+      base::StringPrintf("%d%%", (int)(value_ * 100 + 0.5)));
+}
+
 }  // namespace views