Send input event IPCs directly from the UI thread

ipc/ipc_channel_proxy.cc

Index: ipc/ipc_channel_proxy.cc
diff --git a/ipc/ipc_channel_proxy.cc b/ipc/ipc_channel_proxy.cc
index b3424124158d5034c5cd142c8779a81c17c83923..bd368850cdcfb429a2fddfd7853145cb72309a68 100644
--- a/ipc/ipc_channel_proxy.cc
+++ b/ipc/ipc_channel_proxy.cc
@@ -318,23 +318,22 @@ void ChannelProxy::Context::ClearChannel() {
   channel_.reset();
 }
 
-void ChannelProxy::Context::SendFromThisThread(Message* message) {
+bool ChannelProxy::Context::SendFromThisThread(Message* message) {
   base::AutoLock l(channel_lifetime_lock_);
   if (!channel_)
-    return;
+    return false;
   DCHECK(channel_->IsSendThreadSafe());
-  channel_->Send(message);
+  return channel_->Send(message);
 }
 
-void ChannelProxy::Context::Send(Message* message) {
-  if (channel_send_thread_safe_) {
-    SendFromThisThread(message);
-    return;
-  }
+bool ChannelProxy::Context::Send(Message* message, bool force_io_thread) {
+  if (channel_send_thread_safe_ && !force_io_thread)
+    return SendFromThisThread(message);
 
   ipc_task_runner()->PostTask(
       FROM_HERE, base::Bind(&ChannelProxy::Context::OnSendMessage, this,
                             base::Passed(base::WrapUnique(message))));
+  return true;
 }
 
 bool ChannelProxy::Context::IsChannelSendThreadSafe() const {
@@ -377,11 +376,7 @@ ChannelProxy::ChannelProxy(Context* context)
 ChannelProxy::ChannelProxy(
     Listener* listener,
     const scoped_refptr<base::SingleThreadTaskRunner>& ipc_task_runner)
-    : context_(new Context(listener, ipc_task_runner)), did_init_(false) {
-#if defined(ENABLE_IPC_FUZZER)
-  outgoing_message_filter_ = NULL;
-#endif
-}
+    : ChannelProxy(new Context(listener, ipc_task_runner)) {}
 
 ChannelProxy::~ChannelProxy() {
   DCHECK(CalledOnValidThread());
@@ -444,25 +439,15 @@ void ChannelProxy::Close() {
 }
 
 bool ChannelProxy::Send(Message* message) {
-  DCHECK(did_init_);
-
-  // TODO(alexeypa): add DCHECK(CalledOnValidThread()) here. Currently there are
-  // tests that call Send() from a wrong thread. See http://crbug.com/163523.
-
-#ifdef ENABLE_IPC_FUZZER
-  // In IPC fuzzing builds, it is possible to define a filter to apply to
-  // outgoing messages. It will either rewrite the message and return a new
-  // one, freeing the original, or return the message unchanged.
-  if (outgoing_message_filter())
-    message = outgoing_message_filter()->Rewrite(message);
-#endif
+  return SendOnIPCThread(message);
+}
 
-#ifdef IPC_MESSAGE_LOG_ENABLED
-  Logging::GetInstance()->OnSendMessage(message, context_->channel_id());
-#endif
+bool ChannelProxy::SendNow(Message* message) {
+  return SendImpl(message, false /* force_io_thread */);
+}
 
-  context_->Send(message);
-  return true;
+bool ChannelProxy::SendOnIPCThread(Message* message) {
+  return SendImpl(message, true /* force_io_thread */);
 }
 
 void ChannelProxy::AddFilter(MessageFilter* filter) {
@@ -519,6 +504,27 @@ base::ScopedFD ChannelProxy::TakeClientFileDescriptor() {
 void ChannelProxy::OnChannelInit() {
 }
 
+bool ChannelProxy::SendImpl(Message* message, bool force_io_thread) {
+  DCHECK(did_init_);
+
+  // TODO(alexeypa): add DCHECK(CalledOnValidThread()) here. Currently there are
+  // tests that call Send() from a wrong thread. See http://crbug.com/163523.
+
+#ifdef ENABLE_IPC_FUZZER
+  // In IPC fuzzing builds, it is possible to define a filter to apply to
+  // outgoing messages. It will either rewrite the message and return a new
+  // one, freeing the original, or return the message unchanged.
+  if (outgoing_message_filter())
+    message = outgoing_message_filter()->Rewrite(message);
+#endif
+
+#ifdef IPC_MESSAGE_LOG_ENABLED
+  Logging::GetInstance()->OnSendMessage(message, context_->channel_id());
+#endif
+
+  return context_->Send(message, force_io_thread);
+}
+
 //-----------------------------------------------------------------------------
 
 }  // namespace IPC