gpu: Reuse transfer buffers more aggresively

gpu/command_buffer/client/buffer_tracker.h

Index: gpu/command_buffer/client/buffer_tracker.h
diff --git a/gpu/command_buffer/client/buffer_tracker.h b/gpu/command_buffer/client/buffer_tracker.h
index 3e50364317d234bc9d7ed336c81de4fdbc26d5a4..33bd94b04561b74640f81579987f741c45a9b254 100644
--- a/gpu/command_buffer/client/buffer_tracker.h
+++ b/gpu/command_buffer/client/buffer_tracker.h
@@ -35,7 +35,8 @@ class GLES2_IMPL_EXPORT BufferTracker {
           shm_offset_(shm_offset),
           address_(address),
           mapped_(false),
-          transfer_ready_token_(0) {
+          last_usage_token_(0),
+          last_async_upload_token_(0) {
     }
 
     GLenum id() const {
@@ -66,12 +67,20 @@ class GLES2_IMPL_EXPORT BufferTracker {
       return mapped_;
     }
 
-    void set_transfer_ready_token(int token) {
-      transfer_ready_token_ = token;
+    void set_last_usage_token(int token) {
+      last_usage_token_ = token;
     }
 
-    uint32 transfer_ready_token() const {
-      return transfer_ready_token_;
+    int last_usage_token() const {
+      return last_usage_token_;
+    }
+
+    void set_last_async_upload_token(uint32 async_token) {
+      last_async_upload_token_ = async_token;
+    }
+
+    GLuint last_async_upload_token() const {
+      return last_async_upload_token_;
     }
 
    private:
@@ -84,7 +93,8 @@ class GLES2_IMPL_EXPORT BufferTracker {
     uint32 shm_offset_;
     void* address_;
     bool mapped_;
-    int32 transfer_ready_token_;
+    int32 last_usage_token_;
+    GLuint last_async_upload_token_;
   };
 
   BufferTracker(MappedMemoryManager* manager);
@@ -96,7 +106,9 @@ class GLES2_IMPL_EXPORT BufferTracker {
 
   // Frees the block of memory associated with buffer, pending the passage
   // of a token.
-  void FreePendingToken(Buffer*, int32 token);
+  void FreePendingToken(Buffer* buffer, int32 token);
+  void Unmanage(Buffer* buffer);
+  void Free(Buffer* buffer);
 
  private:
   typedef base::hash_map<GLuint, Buffer*> BufferMap;