Delay the response to ChildProcessHostMsg_SyncAllocateGpuMemoryBuffer via a callback to allow for b…

content/browser/renderer_host/render_message_filter.cc

Index: content/browser/renderer_host/render_message_filter.cc
diff --git a/content/browser/renderer_host/render_message_filter.cc b/content/browser/renderer_host/render_message_filter.cc
index 11f80eeab63347999c3ab2deddfe6bc4096a74a3..7c32a5aa299cec1631baba93078ede2eff05f26a 100644
--- a/content/browser/renderer_host/render_message_filter.cc
+++ b/content/browser/renderer_host/render_message_filter.cc
@@ -239,6 +239,19 @@ void AddIntegerValue(CFMutableDictionaryRef dictionary,
 }
 #endif
 
+class ScopedCallbackRunner {
+ public:
+  ScopedCallbackRunner(base::Closure* callback) : callback_(callback) {}
+  ~ScopedCallbackRunner() {
+    if (callback_)
+      callback_->Run();
+  }
+  void reset() { callback_ = NULL; }
+
+ private:
+  base::Closure* callback_;
+};
+
 }  // namespace
 
 class RenderMessageFilter::OpenChannelToNpapiPluginCallback
@@ -443,8 +456,9 @@ bool RenderMessageFilter::OnMessageReceived(const IPC::Message& message,
                         OnAllocateSharedMemory)
     IPC_MESSAGE_HANDLER(ChildProcessHostMsg_SyncAllocateSharedBitmap,
                         OnAllocateSharedBitmap)
-    IPC_MESSAGE_HANDLER(ChildProcessHostMsg_SyncAllocateGpuMemoryBuffer,
-                        OnAllocateGpuMemoryBuffer)
+    IPC_MESSAGE_HANDLER_DELAY_REPLY(
+        ChildProcessHostMsg_SyncAllocateGpuMemoryBuffer,
+        OnAllocateGpuMemoryBuffer)
     IPC_MESSAGE_HANDLER(ChildProcessHostMsg_AllocatedSharedBitmap,
                         OnAllocatedSharedBitmap)
     IPC_MESSAGE_HANDLER(ChildProcessHostMsg_DeletedSharedBitmap,
@@ -1233,12 +1247,20 @@ void RenderMessageFilter::OnWebAudioMediaCodec(
 }
 #endif
 
-void RenderMessageFilter::OnAllocateGpuMemoryBuffer(
-    uint32 width,
-    uint32 height,
-    uint32 internalformat,
-    uint32 usage,
-    gfx::GpuMemoryBufferHandle* handle) {
+void RenderMessageFilter::OnAllocateGpuMemoryBuffer(uint32 width,
+                                                    uint32 height,
+                                                    uint32 internalformat,
+                                                    uint32 usage,
+                                                    IPC::Message* reply) {
+  gfx::GpuMemoryBufferHandle* handle = new gfx::GpuMemoryBufferHandle;

[reveman, 2014/05/19 05:51:07]

I prefer if you don't heap allocate this. Seems unnecessary and ownership passed
to the callback using base::Owned is a bit too subtle for my taste.

+
+  base::Closure reply_callback =
+      base::Bind(&RenderMessageFilter::SendAllocateGpuMemoryBufferReply,
+                 this,
+                 reply,
+                 base::Owned(handle));
+  ScopedCallbackRunner callback_runner(&reply_callback);

[reveman, 2014/05/19 05:51:07]

I prefer if you called ::GpuMemoryBufferAllocated directly instead. And just
used base::Bind below when you call 
GpuMemoryBufferImpl::AllocateForChildProcess. Basically replacing "handle->type
= gfx::EMPTY_BUFFER" below with "GpuMemoryBufferAllocated(reply,
gfx::GpuMemoryBufferHandle())".

+
   if (!GpuMemoryBufferImpl::IsFormatValid(internalformat) ||
       !GpuMemoryBufferImpl::IsUsageValid(usage)) {
     handle->type = gfx::EMPTY_BUFFER;
@@ -1320,9 +1342,22 @@ void RenderMessageFilter::OnAllocateGpuMemoryBuffer(
     }
   }
 #endif
+  callback_runner.reset();
+
+  GpuMemoryBufferImpl::AllocateForChildProcess(gfx::Size(width, height),
+                                               internalformat,
+                                               usage,
+                                               PeerHandle(),
+                                               handle,
+                                               reply_callback);
+}
 
-  GpuMemoryBufferImpl::AllocateForChildProcess(
-      gfx::Size(width, height), internalformat, usage, PeerHandle(), handle);
+void RenderMessageFilter::SendAllocateGpuMemoryBufferReply(
+    IPC::Message* reply,
+    gfx::GpuMemoryBufferHandle* handle) {
+  ChildProcessHostMsg_SyncAllocateGpuMemoryBuffer::WriteReplyParams(reply,
+                                                                    *handle);
+  Send(reply);
 }
 
 }  // namespace content