[Merge to 2743] Revert "[Reland 2] Pepper takes ownership of a mailbox before passing it to the tex…

gpu/ipc/service/gpu_channel.cc

Index: gpu/ipc/service/gpu_channel.cc
diff --git a/gpu/ipc/service/gpu_channel.cc b/gpu/ipc/service/gpu_channel.cc
index 9ab4f860b9096e9773b68f193e4ac60abe39a199..1a777631b29cad1d6c14789fbc380d7ac8abee3e 100644
--- a/gpu/ipc/service/gpu_channel.cc
+++ b/gpu/ipc/service/gpu_channel.cc
@@ -792,10 +792,8 @@ void GpuChannel::HandleMessage(
   HandleMessageHelper(msg);
 
   // If we get descheduled or yield while processing a message.
-  if ((stub && stub->HasUnprocessedCommands()) ||
-      !message_queue->IsScheduled()) {
-    DCHECK((uint32_t)GpuCommandBufferMsg_AsyncFlush::ID == msg.type() ||
-           (uint32_t)GpuCommandBufferMsg_WaitSyncToken::ID == msg.type());
+  if (stub && stub->HasUnprocessedCommands()) {
+    DCHECK_EQ((uint32_t)GpuCommandBufferMsg_AsyncFlush::ID, msg.type());
     message_queue->PauseMessageProcessing();
   } else {
     message_queue->FinishMessageProcessing();