RendererGLContext supports reparenting a GL context.

content/common/gpu/gpu_messages.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.
 
 #include <vector>
 #include <string>
 
 
 #include "base/shared_memory.h"
 #include "content/common/common_param_traits.h"
@@ skipping 213 matching lines @@
 // These are messages from a renderer process to the GPU process.
 
 // Initialize a channel between a renderer process and a GPU process. The
 // renderer passes its process handle to the GPU process, which gives gives the
 // GPU process the ability to map handles from the renderer process. This must
 // be the first message sent on a newly connected channel.
 IPC_MESSAGE_CONTROL1(GpuChannelMsg_Initialize,
                      base::ProcessHandle /* renderer_process_for_gpu */)
 
 // Tells the GPU process to create a new command buffer that renders to an
-// offscreen frame buffer. If parent_route_id is not zero, the texture backing
-// the frame buffer is mapped into the corresponding parent command buffer's
-// namespace, with the name of parent_texture_id. This ID is in the parent's
-// namespace.
-IPC_SYNC_MESSAGE_CONTROL4_1(GpuChannelMsg_CreateOffscreenCommandBuffer,
-                            int32, /* parent_route_id */
+// offscreen frame buffer.
+IPC_SYNC_MESSAGE_CONTROL2_1(GpuChannelMsg_CreateOffscreenCommandBuffer,
                             gfx::Size, /* size */
                             GPUCreateCommandBufferConfig, /* init_params */
-                            uint32, /* parent_texture_id */
                             int32 /* route_id */)
 
 // The CommandBufferProxy sends this to the GpuCommandBufferStub in its
 // destructor, so that the stub deletes the actual CommandBufferService
 // object that it's hosting.
 // TODO(apatrick): Implement this.
 IPC_SYNC_MESSAGE_CONTROL1_0(GpuChannelMsg_DestroyCommandBuffer,
                             int32 /* instance_id */)
 
 // Create a surface for offscreen rendering.
@@ skipping 36 matching lines @@
 // These are messages between a renderer process to the GPU process relating to
 // a single OpenGL context.
 // Initialize a command buffer with the given number of command entries.
 // Returns the shared memory handle for the command buffer mapped to the
 // calling process.
 IPC_SYNC_MESSAGE_ROUTED2_1(GpuCommandBufferMsg_Initialize,
                            base::SharedMemoryHandle /* ring_buffer */,
                            int32 /* size */,
                            bool /* result */)
 
+// Sets the parent command buffer. This allows the parent and child to share
+// textures.
+IPC_SYNC_MESSAGE_ROUTED2_1(GpuCommandBufferMsg_SetParent,
+                           int32 /* parent_route_id */,
+                           uint32 /* parent_texture_id */,
+                           bool /* result */)
+
 // Get the current state of the command buffer.
 IPC_SYNC_MESSAGE_ROUTED0_1(GpuCommandBufferMsg_GetState,
                            gpu::CommandBuffer::State /* state */)
 
 // Synchronize the put and get offsets of both processes. Caller passes its
 // current put offset. Current state (including get offset) is returned.
 IPC_SYNC_MESSAGE_ROUTED3_1(GpuCommandBufferMsg_Flush,
                            int32 /* put_offset */,
                            int32 /* last_known_get */,
                            uint32 /* flush_count */,
@@ skipping 180 matching lines @@
 
 // Confirm decoder has been aborted.
 IPC_MESSAGE_ROUTED0(AcceleratedVideoDecoderHostMsg_AbortDone)
 
 // Decoder has faced end of stream marker in the stream.
 IPC_MESSAGE_ROUTED0(AcceleratedVideoDecoderHostMsg_EndOfStream)
 
 // Video decoder has encountered an error.
 IPC_MESSAGE_ROUTED1(AcceleratedVideoDecoderHostMsg_ErrorNotification,
                     uint32) /* Error ID */