Switching to base::Optional<CompositorFrame> in Android's synchronous compositor IPC messages

content/common/android/sync_compositor_messages.h

 // Copyright 2015 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 <stddef.h>
 
 #include "base/memory/shared_memory_handle.h"
 #include "cc/output/begin_frame_args.h"
 #include "cc/output/compositor_frame.h"
 #include "content/common/content_export.h"
@@ skipping 109 matching lines @@
     SyncCompositorMsg_SynchronizeRendererState,
     std::vector<int> /* routing ids*/,
     std::vector<content::SyncCompositorCommonRendererParams>)
 
 IPC_MESSAGE_ROUTED1(SyncCompositorMsg_ComputeScroll,
                     base::TimeTicks);
 
 IPC_MESSAGE_ROUTED1(SyncCompositorMsg_DemandDrawHwAsync,
                     content::SyncCompositorDemandDrawHwParams)
 
-IPC_SYNC_MESSAGE_ROUTED1_3(SyncCompositorMsg_DemandDrawHw,
+IPC_SYNC_MESSAGE_ROUTED1_4(SyncCompositorMsg_DemandDrawHw,
                            content::SyncCompositorDemandDrawHwParams,
                            content::SyncCompositorCommonRendererParams,
                            uint32_t /* compositor_frame_sink_id */,
-                           cc::CompositorFrame)
+                           cc::CompositorFrame,

[boliu, 2016/10/27 18:11:46]

might be easier to replace this with base::Optional<cc::CompositorFrame> ?

Looks like there's a ParamTraits for base::Optional already, so it should just
work?

+                           bool /* has_swapped */)
 
 IPC_SYNC_MESSAGE_ROUTED1_2(SyncCompositorMsg_SetSharedMemory,
                            content::SyncCompositorSetSharedMemoryParams,
                            bool /* success */,
                            content::SyncCompositorCommonRendererParams);
 
 IPC_MESSAGE_ROUTED0(SyncCompositorMsg_ZeroSharedMemory);
 
 IPC_SYNC_MESSAGE_ROUTED1_3(SyncCompositorMsg_DemandDrawSw,
                            content::SyncCompositorDemandDrawSwParams,
@@ skipping 16 matching lines @@
 IPC_MESSAGE_ROUTED1(SyncCompositorMsg_SetScroll, gfx::ScrollOffset);
 
 // -----------------------------------------------------------------------------
 // Messages sent from the renderer to the browser.
 
 IPC_MESSAGE_ROUTED0(SyncCompositorHostMsg_CompositorFrameSinkCreated);
 
 IPC_MESSAGE_ROUTED1(SyncCompositorHostMsg_UpdateState,
                     content::SyncCompositorCommonRendererParams)
 
-IPC_MESSAGE_ROUTED2(SyncCompositorHostMsg_ReturnFrame,
+IPC_MESSAGE_ROUTED3(SyncCompositorHostMsg_ReturnFrame,
                     uint32_t /* compositor_frame_sink_id */,
-                    cc::CompositorFrame);
+                    cc::CompositorFrame,
+                    bool /* has_swapped */);