Note scrollbar layer properties changed when position changes.

cc/layers/scrollbar_layer_impl.cc

 // Copyright 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 "cc/layers/scrollbar_layer_impl.h"
 
 #include <algorithm>
 
 #include "cc/animation/scrollbar_animation_controller.h"
 #include "cc/layers/layer.h"
@@ skipping 45 matching lines @@
   return ScrollbarLayerImpl::Create(tree_impl,
                                     id(),
                                     orientation_).PassAs<LayerImpl>();
 }
 
 void ScrollbarLayerImpl::PushPropertiesTo(LayerImpl* layer) {
   LayerImpl::PushPropertiesTo(layer);
 
   ScrollbarLayerImpl* scrollbar_layer = static_cast<ScrollbarLayerImpl*>(layer);
 
-  scrollbar_layer->set_thumb_thickness(thumb_thickness_);
-  scrollbar_layer->set_thumb_length(thumb_length_);
-  scrollbar_layer->set_track_start(track_start_);
-  scrollbar_layer->set_track_length(track_length_);
+  scrollbar_layer->SetThumbThickness(thumb_thickness_);
+  scrollbar_layer->SetThumbLength(thumb_length_);
+  scrollbar_layer->SetTrackStart(track_start_);
+  scrollbar_layer->SetTrackLength(track_length_);
   scrollbar_layer->set_is_overlay_scrollbar(is_overlay_scrollbar_);
 
   scrollbar_layer->set_track_resource_id(track_resource_id_);
   scrollbar_layer->set_thumb_resource_id(thumb_resource_id_);
 }
 
 bool ScrollbarLayerImpl::WillDraw(DrawMode draw_mode,
                                   ResourceProvider* resource_provider) {
   if (draw_mode == DRAW_MODE_RESOURCELESS_SOFTWARE &&
       !layer_tree_impl()->settings().solid_color_scrollbars)
@@ skipping 83 matching lines @@
 gfx::Rect ScrollbarLayerImpl::ScrollbarLayerRectToContentRect(
     gfx::RectF layer_rect) const {
   // Don't intersect with the bounds as in layerRectToContentRect() because
   // layer_rect here might be in coordinates of the containing layer.
   gfx::RectF content_rect = gfx::ScaleRect(layer_rect,
                                            contents_scale_x(),
                                            contents_scale_y());
   return gfx::ToEnclosingRect(content_rect);
 }
 
+void ScrollbarLayerImpl::SetThumbThickness(int thumb_thickness) {
+  if (thumb_thickness_ == thumb_thickness)
+    return;
+  thumb_thickness_ = thumb_thickness;
+  NoteLayerPropertyChanged();
+}
+
+void ScrollbarLayerImpl::SetThumbLength(int thumb_length) {
+  if (thumb_length_ == thumb_length)
+    return;
+  thumb_length_ = thumb_length;
+  NoteLayerPropertyChanged();
+}
+void ScrollbarLayerImpl::SetTrackStart(int track_start) {
+  if (track_start_ == track_start)
+    return;
+  track_start_ = track_start;
+  NoteLayerPropertyChanged();
+}
+
+void ScrollbarLayerImpl::SetTrackLength(int track_length) {
+  if (track_length_ == track_length)
+    return;
+  track_length_ = track_length;
+  NoteLayerPropertyChanged();
+}
+
+void ScrollbarLayerImpl::SetVerticalAdjust(float vertical_adjust) {
+  if (vertical_adjust_ == vertical_adjust)
+    return;
+  vertical_adjust_ = vertical_adjust;
+  NoteLayerPropertyChanged();
+}
+
+void ScrollbarLayerImpl::SetVisibleToTotalLengthRatio(float ratio) {
+  if (visible_to_total_length_ratio_ == ratio)
+    return;
+  visible_to_total_length_ratio_ = ratio;
+  NoteLayerPropertyChanged();
+}
+
 void ScrollbarLayerImpl::SetCurrentPos(float current_pos) {
+  if (current_pos_ == current_pos)
+    return;
   current_pos_ = current_pos;
   NoteLayerPropertyChanged();
 }
 
 void ScrollbarLayerImpl::SetMaximum(int maximum) {
+  if (maximum_ == maximum)
+    return;
   maximum_ = maximum;
   NoteLayerPropertyChanged();
 }
 
 gfx::Rect ScrollbarLayerImpl::ComputeThumbQuadRect() const {
   // Thumb extent is the length of the thumb in the scrolling direction, thumb
   // thickness is in the perpendicular direction. Here's an example of a
   // horizontal scrollbar - inputs are above the scrollbar, computed values
   // below:
   //
@@ skipping 85 matching lines @@
 void ScrollbarLayerImpl::DidLoseOutputSurface() {
   track_resource_id_ = 0;
   thumb_resource_id_ = 0;
 }
 
 const char* ScrollbarLayerImpl::LayerTypeAsString() const {
   return "cc::ScrollbarLayerImpl";
 }
 
 }  // namespace cc