gpu: Reuse transfer buffers more aggresively

gpu/command_buffer/service/query_manager.h

Index: gpu/command_buffer/service/query_manager.h
diff --git a/gpu/command_buffer/service/query_manager.h b/gpu/command_buffer/service/query_manager.h
index d77982b897fc161867a23c50ef3013b91e5a3d73..59ccbb70a626b1b1c36399e7643f81758a2789ae 100644
--- a/gpu/command_buffer/service/query_manager.h
+++ b/gpu/command_buffer/service/query_manager.h
@@ -26,7 +26,7 @@ class FeatureInfo;
 
 // This class keeps track of the queries and their state
 // As Queries are not shared there is one QueryManager per context.
-class GPU_EXPORT QueryManager {
+class GPU_EXPORT QueryManager : public base::SupportsWeakPtr<QueryManager> {
  public:
   class GPU_EXPORT Query : public base::RefCounted<Query> {
    public:
@@ -57,6 +57,14 @@ class GPU_EXPORT QueryManager {
       return shm_offset_;
     }
 
+    void set_serial(uint32 serial) {
+      serial_ = serial;
+    }
+
+    uint32 serial() const {
+      return serial_;
+    }
+
     // Returns false if shared memory for sync is invalid.
     virtual bool Begin() = 0;
 
@@ -143,6 +151,8 @@ class GPU_EXPORT QueryManager {
     // True if deleted.
     bool deleted_;
 
+    uint32 serial_;
+
     // List of callbacks to run when result is available.
     std::vector<base::Closure> callbacks_;
   };