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

content/common/android/sync_compositor_messages.h

Index: content/common/android/sync_compositor_messages.h
diff --git a/content/common/android/sync_compositor_messages.h b/content/common/android/sync_compositor_messages.h
index e7e41d6e5d0d5d744a63be8402a8644cdfe1fd79..5ef13bf7811055caf2b4b5168c50bc5a2c0a7dc8 100644
--- a/content/common/android/sync_compositor_messages.h
+++ b/content/common/android/sync_compositor_messages.h
@@ -5,6 +5,7 @@
 #include <stddef.h>
 
 #include "base/memory/shared_memory_handle.h"
+#include "base/optional.h"
 #include "cc/output/begin_frame_args.h"
 #include "cc/output/compositor_frame.h"
 #include "content/common/content_export.h"
@@ -131,7 +132,7 @@ IPC_SYNC_MESSAGE_ROUTED1_3(SyncCompositorMsg_DemandDrawHw,
                            content::SyncCompositorDemandDrawHwParams,
                            content::SyncCompositorCommonRendererParams,
                            uint32_t /* compositor_frame_sink_id */,
-                           cc::CompositorFrame)
+                           base::Optional<cc::CompositorFrame>);
 
 IPC_SYNC_MESSAGE_ROUTED1_2(SyncCompositorMsg_SetSharedMemory,
                            content::SyncCompositorSetSharedMemoryParams,
@@ -170,4 +171,4 @@ IPC_MESSAGE_ROUTED1(SyncCompositorHostMsg_UpdateState,
 
 IPC_MESSAGE_ROUTED2(SyncCompositorHostMsg_ReturnFrame,
                     uint32_t /* compositor_frame_sink_id */,
-                    cc::CompositorFrame);
+                    base::Optional<cc::CompositorFrame>);