Make IsSolidColor() a property on CC scrollbar layers.

cc/trees/layer_tree_host_unittest.cc

Index: cc/trees/layer_tree_host_unittest.cc
diff --git a/cc/trees/layer_tree_host_unittest.cc b/cc/trees/layer_tree_host_unittest.cc
index 849cb38d62d52d6e23a258dcbd53f4e4d1bc6b04..0262b94e4fece809d43cf64b87b5b0e08927902f 100644
--- a/cc/trees/layer_tree_host_unittest.cc
+++ b/cc/trees/layer_tree_host_unittest.cc
@@ -421,7 +421,8 @@ class LayerTreeHostTestNoExtraCommitFromScrollbarInvalidate
     bool has_thumb = false;
     scrollbar_ = FakeScrollbarLayer::Create(paint_scrollbar,
                                             has_thumb,
-                                            root_layer_->id());
+                                            root_layer_->id(),
+                                            false);
     scrollbar_->SetPosition(gfx::Point(0, 10));
     scrollbar_->SetBounds(gfx::Size(10, 10));
 
@@ -1145,8 +1146,8 @@ class LayerTreeHostTestAtomicCommit : public LayerTreeHostTest {
 
     bool paint_scrollbar = true;
     bool has_thumb = false;
-    scrollbar_ =
-        FakeScrollbarLayer::Create(paint_scrollbar, has_thumb, layer_->id());
+    scrollbar_ = FakeScrollbarLayer::Create(
+        paint_scrollbar, has_thumb, layer_->id(), false);
     scrollbar_->SetPosition(gfx::Point(0, 10));
     scrollbar_->SetBounds(gfx::Size(10, 10));
 
@@ -1276,14 +1277,14 @@ class LayerTreeHostTestAtomicCommitWithPartialUpdate
 
     bool paint_scrollbar = true;
     bool has_thumb = false;
-    scrollbar_with_paints_ =
-        FakeScrollbarLayer::Create(paint_scrollbar, has_thumb, parent_->id());
+    scrollbar_with_paints_ = FakeScrollbarLayer::Create(
+        paint_scrollbar, has_thumb, parent_->id(), false);
     scrollbar_with_paints_->SetPosition(gfx::Point(3, 10));
     scrollbar_with_paints_->SetBounds(gfx::Size(3, 10));
 
     paint_scrollbar = false;
-    scrollbar_without_paints_ =
-        FakeScrollbarLayer::Create(paint_scrollbar, has_thumb, parent_->id());
+    scrollbar_without_paints_ = FakeScrollbarLayer::Create(
+        paint_scrollbar, has_thumb, parent_->id(), false);
     scrollbar_without_paints_->SetPosition(gfx::Point(6, 10));
     scrollbar_without_paints_->SetBounds(gfx::Size(3, 10));
 
@@ -2887,7 +2888,7 @@ class LayerTreeHostTestDeferredInitialize : public LayerTreeHostTest {
   virtual void InitializeSettings(LayerTreeSettings* settings) OVERRIDE {
     // PictureLayer can only be used with impl side painting enabled.
     settings->impl_side_painting = true;
-    settings->solid_color_scrollbars = true;
+    settings->force_solid_color_scrollbars = true;
   }
 
   virtual void SetupTree() OVERRIDE {