Make IsSolidColor() a property on CC scrollbar layers.

cc/trees/layer_tree_impl.cc

 // Copyright 2011 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/trees/layer_tree_impl.h"
 
 #include "base/debug/trace_event.h"
 #include "cc/animation/keyframed_animation_curve.h"
 #include "cc/animation/scrollbar_animation_controller.h"
 #include "cc/debug/traced_value.h"
@@ skipping 205 matching lines @@
       gfx::RectF(ScrollableViewportSize()).bottom_right();
 
   // The viewport may be larger than the contents in some cases, such as
   // having a vertical scrollbar but no horizontal overflow.
   max_scroll.SetToMax(gfx::Vector2dF());
 
   root_scroll_layer_->SetMaxScrollOffset(gfx::ToFlooredVector2d(max_scroll));
 }
 
 void LayerTreeImpl::UpdateSolidColorScrollbars() {
-  DCHECK(settings().solid_color_scrollbars);
+  // TODO(wjmaclean) This logic will need to change when we re-factor
+  // RootScrollLayer() into InnerViewportScrollLayer() and
+  // OuterViewportScrollLayer(), since in the desktop case the
+  // OuterViewportScrollLayer() won't have solid color
+  // scrollbars, while the InnerViewportScrollLayer() will. Ultimately, the
+  // plan is for this function to disappear altogether.
+  DCHECK(settings().force_solid_color_scrollbars);
 
   LayerImpl* root_scroll = RootScrollLayer();
   DCHECK(root_scroll);
   DCHECK(IsActiveTree());
 
   gfx::RectF scrollable_viewport(
       gfx::PointAtOffsetFromOrigin(root_scroll->TotalScrollOffset()),
       ScrollableViewportSize());
   float vertical_adjust = 0.0f;
   if (RootClipLayer())
     vertical_adjust = layer_tree_host_impl_->VisibleViewportSize().height() -
                       RootClipLayer()->bounds().height();
   if (ScrollbarLayerImpl* horiz = root_scroll->horizontal_scrollbar_layer()) {
     horiz->set_vertical_adjust(vertical_adjust);
     horiz->set_visible_to_total_length_ratio(
         scrollable_viewport.width() / ScrollableSize().width());
   }
   if (ScrollbarLayerImpl* vertical = root_scroll->vertical_scrollbar_layer()) {
     vertical->set_vertical_adjust(vertical_adjust);
     vertical->set_visible_to_total_length_ratio(
         scrollable_viewport.height() / ScrollableSize().height());
   }
 }
 
 void LayerTreeImpl::UpdateDrawProperties() {
   if (IsActiveTree() && RootScrollLayer() && RootClipLayer())
     UpdateRootScrollLayerSizeDelta();
 
-  if (settings().solid_color_scrollbars &&
+  if (settings().force_solid_color_scrollbars &&
       IsActiveTree() &&
       RootScrollLayer()) {
     UpdateSolidColorScrollbars();
 
     // The top controls manager is incompatible with the WebKit-created cliprect
     // because it can bring into view a larger amount of content when it
     // hides. It's safe to deactivate the clip rect if no non-overlay scrollbars
     // are present.
     if (RootClipLayer() && layer_tree_host_impl_->top_controls_manager())
       RootClipLayer()->SetMasksToBounds(false);
@@ skipping 284 matching lines @@
 
 void LayerTreeImpl::ClearLatencyInfo() {
   latency_info_.Clear();
 }
 
 void LayerTreeImpl::WillModifyTilePriorities() {
   layer_tree_host_impl_->SetNeedsManageTiles();
 }
 
 }  // namespace cc