cc: Clarify that color spaces are for raster

cc/trees/layer_tree_impl.h

Index: cc/trees/layer_tree_impl.h
diff --git a/cc/trees/layer_tree_impl.h b/cc/trees/layer_tree_impl.h
index 02c6e994d3d680dbdfe9df53c335b6183ff03d08..8ccd09b46fe4e1e3fc1cbcdd82b946255da771cd 100644
--- a/cc/trees/layer_tree_impl.h
+++ b/cc/trees/layer_tree_impl.h
@@ -232,9 +232,9 @@ class CC_EXPORT LayerTreeImpl {
   void set_content_source_id(uint32_t id) { content_source_id_ = id; }
   uint32_t content_source_id() { return content_source_id_; }
 
-  void SetDeviceColorSpace(const gfx::ColorSpace& device_color_space);
-  const gfx::ColorSpace& device_color_space() const {
-    return device_color_space_;
+  void SetRasterColorSpace(const gfx::ColorSpace& raster_color_space);
+  const gfx::ColorSpace& raster_color_space() const {
+    return raster_color_space_;
   }
 
   SyncedElasticOverscroll* elastic_overscroll() {
@@ -496,7 +496,7 @@ class CC_EXPORT LayerTreeImpl {
 
   float device_scale_factor_;
   float painted_device_scale_factor_;
-  gfx::ColorSpace device_color_space_;
+  gfx::ColorSpace raster_color_space_;
 
   uint32_t content_source_id_;