WIP: Propagate SurfaceID up window tree hierarchy

cc/surfaces/surface_sequence_generator.h

Index: cc/surfaces/surface_sequence_generator.h
diff --git a/cc/trees/surface_sequence_generator.h b/cc/surfaces/surface_sequence_generator.h
similarity index 65%
rename from cc/trees/surface_sequence_generator.h
rename to cc/surfaces/surface_sequence_generator.h
index 10b880ad5fb84d3ac2143b1e54a60abe1aa8446f..24ae2020e05c412ed4396169b2136bab6b77a1a0 100644
--- a/cc/trees/surface_sequence_generator.h
+++ b/cc/surfaces/surface_sequence_generator.h
@@ -2,14 +2,18 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CC_TREES_SURFACE_SEQUENCE_GENERATOR_H_
-#define CC_TREES_SURFACE_SEQUENCE_GENERATOR_H_
+#ifndef CC_SURFACES_SURFACE_SEQUENCE_GENERATOR_H_
+#define CC_SURFACES_SURFACE_SEQUENCE_GENERATOR_H_
 
 #include <stdint.h>
 
+#include <tuple>
+
 #include "base/macros.h"
 #include "cc/base/cc_export.h"
 
+#include "cc/surfaces/frame_sink_id.h"
+
 namespace cc {
 struct SurfaceSequence;
 
@@ -19,14 +23,14 @@ class CC_EXPORT SurfaceSequenceGenerator {
   SurfaceSequenceGenerator();
   ~SurfaceSequenceGenerator();
 
-  void set_surface_client_id(uint32_t client_id) {
-    surface_client_id_ = client_id;
+  void set_frame_sink_id(const FrameSinkId& frame_sink_id) {
+    frame_sink_id_ = frame_sink_id;
   }
 
   SurfaceSequence CreateSurfaceSequence();
 
  private:
-  uint32_t surface_client_id_;
+  FrameSinkId frame_sink_id_;
   uint32_t next_surface_sequence_;
 
   DISALLOW_COPY_AND_ASSIGN(SurfaceSequenceGenerator);
@@ -34,4 +38,4 @@ class CC_EXPORT SurfaceSequenceGenerator {
 
 }  // namespace cc
 
-#endif  // CC_TREES_SURFACE_SEQUENCE_GENERATOR_H_
+#endif  // CC_SURFACES_SURFACE_SEQUENCE_GENERATOR_H_