Remove QuadCuller class and make QuadSink concrete

cc/trees/layer_tree_host_impl.cc

Index: cc/trees/layer_tree_host_impl.cc
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index 1bc708d5f39fa80a60c61cbf48ec998a78a49dc7..f94bcde53ff5dba902414855d0992ec6e820a583 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -32,6 +32,7 @@
 #include "cc/layers/layer_impl.h"
 #include "cc/layers/layer_iterator.h"
 #include "cc/layers/painted_scrollbar_layer_impl.h"
+#include "cc/layers/quad_sink.h"
 #include "cc/layers/render_surface_impl.h"
 #include "cc/layers/scrollbar_layer_impl_base.h"
 #include "cc/output/compositor_frame_metadata.h"
@@ -60,7 +61,6 @@
 #include "cc/trees/layer_tree_host_common.h"
 #include "cc/trees/layer_tree_impl.h"
 #include "cc/trees/occlusion_tracker.h"
-#include "cc/trees/quad_culler.h"
 #include "cc/trees/single_thread_proxy.h"
 #include "cc/trees/tree_synchronizer.h"
 #include "gpu/GLES2/gl2extchromium.h"
@@ -589,7 +589,7 @@ static void AppendQuadsForLayer(
     LayerImpl* layer,
     const OcclusionTracker<LayerImpl>& occlusion_tracker,
     AppendQuadsData* append_quads_data) {
-  QuadCuller quad_culler(target_render_pass, layer, occlusion_tracker);
+  QuadSink quad_culler(target_render_pass, &occlusion_tracker);
   layer->AppendQuads(&quad_culler, append_quads_data);
 }
 
@@ -599,7 +599,7 @@ static void AppendQuadsForRenderSurfaceLayer(
     const RenderPass* contributing_render_pass,
     const OcclusionTracker<LayerImpl>& occlusion_tracker,
     AppendQuadsData* append_quads_data) {
-  QuadCuller quad_culler(target_render_pass, layer, occlusion_tracker);
+  QuadSink quad_culler(target_render_pass, &occlusion_tracker);
 
   bool is_replica = false;
   layer->render_surface()->AppendQuads(&quad_culler,
@@ -642,7 +642,7 @@ static void AppendQuadsToFillScreen(
     screen_background_color_region.Intersect(root_scroll_layer_rect);
   }
 
-  QuadCuller quad_culler(target_render_pass, root_layer, occlusion_tracker);
+  QuadSink quad_culler(target_render_pass, &occlusion_tracker);
 
   // Manually create the quad state for the gutter quads, as the root layer
   // doesn't have any bounds and so can't generate this itself.