Make IsSolidColor() a property on CC scrollbar layers.

cc/layers/scrollbar_layer.cc

Index: cc/layers/scrollbar_layer.cc
diff --git a/cc/layers/scrollbar_layer.cc b/cc/layers/scrollbar_layer.cc
index 30e2a93ba5bf453eba0b0d1bcff9965f9dfeacab..3ba1d2384d87ac3987db3977925104d83805ef74 100644
--- a/cc/layers/scrollbar_layer.cc
+++ b/cc/layers/scrollbar_layer.cc
@@ -21,21 +21,26 @@ namespace cc {
 scoped_ptr<LayerImpl> ScrollbarLayer::CreateLayerImpl(
     LayerTreeImpl* tree_impl) {
   return ScrollbarLayerImpl::Create(
-      tree_impl, id(), scrollbar_->Orientation()).PassAs<LayerImpl>();
+      tree_impl, id(), scrollbar_->Orientation(), is_solid_color_)
+      .PassAs<LayerImpl>();
 }
 
 scoped_refptr<ScrollbarLayer> ScrollbarLayer::Create(
     scoped_ptr<Scrollbar> scrollbar,
-    int scroll_layer_id) {
+    int scroll_layer_id,
+    bool is_solid_color) {
   return make_scoped_refptr(new ScrollbarLayer(scrollbar.Pass(),
-                                               scroll_layer_id));
+                                               scroll_layer_id,
+                                               is_solid_color));
 }
 
 ScrollbarLayer::ScrollbarLayer(
     scoped_ptr<Scrollbar> scrollbar,
-    int scroll_layer_id)
+    int scroll_layer_id,
+    bool is_solid_color)
     : scrollbar_(scrollbar.Pass()),
       scroll_layer_id_(scroll_layer_id),
+      is_solid_color_(is_solid_color),
       texture_format_(GL_INVALID_ENUM) {
   if (!scrollbar_->IsOverlay())
     SetShouldScrollOnMainThread(true);
@@ -59,13 +64,19 @@ ScrollbarOrientation ScrollbarLayer::Orientation() const {
   return scrollbar_->Orientation();
 }
 
+bool ScrollbarLayer::IsSolidColor() const {
+  return is_solid_color_ ||
+         (layer_tree_host() &&

[aelias_OOO_until_Jul13, 2013/06/21 23:34:35]

Please DCHECK(layer_tree_host()) instead.

[wjmaclean, 2013/06/24 14:06:41]

Actually, the only reason it's there is that there are unit tests that don't set
layer tree host (so they'll crash without this).

[aelias_OOO_until_Jul13, 2013/06/25 06:54:57]

Can we fix the unit tests instead?  I feel this production change is slightly
dangerous.  There's a risk of creating a texture in the interval before the
layer_tree_host is available.

+          layer_tree_host()->settings().force_solid_color_scrollbars);
+}
+
 int ScrollbarLayer::MaxTextureSize() {
   DCHECK(layer_tree_host());
   return layer_tree_host()->GetRendererCapabilities().max_texture_size;
 }
 
 float ScrollbarLayer::ClampScaleToMaxTextureSize(float scale) {
-  if (layer_tree_host()->settings().solid_color_scrollbars)
+  if (IsSolidColor())
     return scale;
 
   // If the scaled content_bounds() is bigger than the max texture size of the
@@ -104,8 +115,7 @@ void ScrollbarLayer::PushPropertiesTo(LayerImpl* layer) {
 
   ScrollbarLayerImpl* scrollbar_layer = static_cast<ScrollbarLayerImpl*>(layer);
 
-  if (layer_tree_host() &&
-      layer_tree_host()->settings().solid_color_scrollbars) {
+  if (layer_tree_host() && IsSolidColor()) {
     int thickness_override =
         layer_tree_host()->settings().solid_color_scrollbar_thickness_dip;
     if (thickness_override != -1) {
@@ -127,6 +137,7 @@ void ScrollbarLayer::PushPropertiesTo(LayerImpl* layer) {
     scrollbar_layer->set_track_start(track_rect_.y());
     scrollbar_layer->set_track_length(track_rect_.height());
   }
+  scrollbar_layer->set_is_solid_color(IsSolidColor());
 
   if (track_ && track_->texture()->have_backing_texture())
     scrollbar_layer->set_track_resource_id(track_->texture()->resource_id());
@@ -174,7 +185,7 @@ class ScrollbarPartPainter : public LayerPainter {
 };
 
 void ScrollbarLayer::CreateUpdaterIfNeeded() {
-  if (layer_tree_host()->settings().solid_color_scrollbars)
+  if (IsSolidColor())
     return;
 
   texture_format_ =
@@ -212,7 +223,7 @@ void ScrollbarLayer::UpdatePart(CachingBitmapContentLayerUpdater* painter,
                                 gfx::Rect rect,
                                 ResourceUpdateQueue* queue,
                                 RenderingStats* stats) {
-  if (layer_tree_host()->settings().solid_color_scrollbars)
+  if (IsSolidColor())
     return;
 
   // Skip painting and uploading if there are no invalidations and
@@ -267,7 +278,7 @@ gfx::Rect ScrollbarLayer::ScrollbarLayerRectToContentRect(
 
 void ScrollbarLayer::SetTexturePriorities(
     const PriorityCalculator& priority_calc) {
-  if (layer_tree_host()->settings().solid_color_scrollbars)
+  if (IsSolidColor())
     return;
 
   if (content_bounds().IsEmpty())
@@ -296,7 +307,7 @@ void ScrollbarLayer::Update(ResourceUpdateQueue* queue,
                             RenderingStats* stats) {
   track_rect_ = scrollbar_->TrackRect();
 
-  if (layer_tree_host()->settings().solid_color_scrollbars)
+  if (IsSolidColor())
     return;
 
   {