gpu: Remove Echo and SwapCompletion GL interfacess

content/common/gpu/gpu_command_buffer_stub.cc

Index: content/common/gpu/gpu_command_buffer_stub.cc
diff --git a/content/common/gpu/gpu_command_buffer_stub.cc b/content/common/gpu/gpu_command_buffer_stub.cc
index f7daa56f27419bdf2064f013b9052753fcbc7371..ab13d0dd80de6eb8b2f1ef4195d70b496de61f30 100644
--- a/content/common/gpu/gpu_command_buffer_stub.cc
+++ b/content/common/gpu/gpu_command_buffer_stub.cc
@@ -225,8 +225,8 @@ bool GpuCommandBufferStub::OnMessageReceived(const IPC::Message& message) {
   // Ensure the appropriate GL context is current before handling any IPC
   // messages directed at the command buffer. This ensures that the message
   // handler can assume that the context is current (not necessary for
-  // Echo, RetireSyncPoint, or WaitSyncPoint).
-  if (decoder_.get() && message.type() != GpuCommandBufferMsg_Echo::ID &&
+  // RetireSyncPoint or WaitSyncPoint).
+  if (decoder_.get() &&
       message.type() != GpuCommandBufferMsg_WaitForTokenInRange::ID &&
       message.type() != GpuCommandBufferMsg_WaitForGetOffsetInRange::ID &&
       message.type() != GpuCommandBufferMsg_RetireSyncPoint::ID) {
@@ -245,7 +245,6 @@ bool GpuCommandBufferStub::OnMessageReceived(const IPC::Message& message) {
                                     OnSetGetBuffer);
     IPC_MESSAGE_HANDLER(GpuCommandBufferMsg_ProduceFrontBuffer,
                         OnProduceFrontBuffer);
-    IPC_MESSAGE_HANDLER(GpuCommandBufferMsg_Echo, OnEcho);
     IPC_MESSAGE_HANDLER_DELAY_REPLY(GpuCommandBufferMsg_WaitForTokenInRange,
                                     OnWaitForTokenInRange);
     IPC_MESSAGE_HANDLER_DELAY_REPLY(GpuCommandBufferMsg_WaitForGetOffsetInRange,
@@ -384,11 +383,6 @@ void GpuCommandBufferStub::ScheduleDelayedWork(int64 delay) {
       base::TimeDelta::FromMilliseconds(delay));
 }
 
-void GpuCommandBufferStub::OnEcho(const IPC::Message& message) {
-  TRACE_EVENT0("gpu", "GpuCommandBufferStub::OnEcho");
-  Send(new IPC::Message(message));
-}
-
 bool GpuCommandBufferStub::MakeCurrent() {
   if (decoder_->MakeCurrent())
     return true;