Execute all GL commands up to the put offset reported by a flush.

gpu/command_buffer/common/command_buffer.h

 // Copyright (c) 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 GPU_COMMAND_BUFFER_COMMON_COMMAND_BUFFER_H_
 #define GPU_COMMAND_BUFFER_COMMON_COMMAND_BUFFER_H_
 
 #include "../common/buffer.h"
 #include "../common/constants.h"
 
@@ skipping 60 matching lines @@
 
   // Initialize the command buffer using the given preallocated buffer.
   virtual bool Initialize(base::SharedMemory* buffer, int32 size) = 0;
 
   // Gets the ring buffer for the command buffer.
   virtual Buffer GetRingBuffer() = 0;
 
   // Returns the current status.
   virtual State GetState() = 0;
 
+  // Returns the last state without synchronizing with the service.
+  virtual State GetLastState() = 0;
+
   // The writer calls this to update its put offset. This ensures the reader
-  // sees the latest added commands, and will eventually process them.
+  // sees the latest added commands, and will eventually process them. On the
+  // service side, commands are processed up to the given put_offset before
+  // subsequent Flushes on the same GpuChannel.
   virtual void Flush(int32 put_offset) = 0;
 
   // The writer calls this to update its put offset. This function returns the
-  // reader's most recent get offset. Does not return until after the put offset
-  // change callback has been invoked. Returns -1 if the put offset is invalid.
-  // If last_known_get is different from the reader's current get pointer, this
-  // function will return immediately, otherwise it guarantees that the reader
-  // has processed some commands before returning (assuming the command buffer
-  // isn't empty and there is no error).
+  // reader's most recent get offset. Does not return until all pending commands
+  // have been executed.
   virtual State FlushSync(int32 put_offset, int32 last_known_get) = 0;
 
   // Sets the current get offset. This can be called from any thread.
   virtual void SetGetOffset(int32 get_offset) = 0;
 
   // Create a transfer buffer and return a handle that uniquely
   // identifies it or -1 on error. id_request lets the caller request a
   // specific id for the transfer buffer, or -1 if the caller does not care.
   // If the requested id can not be fulfilled, a different id will be returned.
   // id_request must be either -1 or between 0 and 100.
@@ skipping 53 matching lines @@
 
   // These want to be private (and const) but can't in order to support
   // pickling.
   int32 last_token_read;
   int32 last_token_written;
 };
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_COMMON_COMMAND_BUFFER_H_