Update Surface ID Terminology

cc/trees/layer_tree_host.h

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_TREES_LAYER_TREE_HOST_H_
 #define CC_TREES_LAYER_TREE_HOST_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 321 matching lines @@
   void RemoveSwapPromiseMonitor(SwapPromiseMonitor* monitor);
 
   // Call this function when you expect there to be a swap buffer.
   // See swap_promise.h for how to use SwapPromise.
   void QueueSwapPromise(std::unique_ptr<SwapPromise> swap_promise);
 
   void BreakSwapPromises(SwapPromise::DidNotSwapReason reason);
 
   size_t num_queued_swap_promises() const { return swap_promise_list_.size(); }
 
-  void set_surface_id_namespace(uint32_t id_namespace);
+  void set_surface_client_id(uint32_t client_id);
   SurfaceSequence CreateSurfaceSequence();
 
   PropertyTrees* property_trees() { return &property_trees_; }
   bool needs_meta_info_recomputation() {
     return needs_meta_info_recomputation_;
   }
 
   void SetLayerTreeMutator(std::unique_ptr<LayerTreeMutator> mutator);
 
   Layer* LayerById(int id) const;
@@ skipping 238 matching lines @@
 
   using LayerIdMap = std::unordered_map<int, Layer*>;
   LayerIdMap layer_id_map_;
 
   using ElementLayersMap = std::unordered_map<ElementId, Layer*, ElementIdHash>;
   ElementLayersMap element_layers_map_;
 
   // Set of layers that need to push properties.
   std::unordered_set<Layer*> layers_that_should_push_properties_;
 
-  uint32_t surface_id_namespace_;
+  uint32_t surface_client_id_;
   uint32_t next_surface_sequence_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHost);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_HOST_H_