fix uninitialized variable warning for vs2012 compilation

content/common/gpu/client/command_buffer_proxy_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/common/gpu/client/command_buffer_proxy_impl.h"
 
 #include "base/callback.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/process_util.h"
@@ skipping 320 matching lines @@
 
   // Check local cache to see if there is already a client side shared memory
   // object for this id.
   TransferBufferMap::iterator it = transfer_buffers_.find(id);
   if (it != transfer_buffers_.end()) {
     return it->second;
   }
 
   // Assuming we are in the renderer process, the service is responsible for
   // duplicating the handle. This might not be true for NaCl.
-  base::SharedMemoryHandle handle;
+  base::SharedMemoryHandle handle = base::SharedMemoryHandle();
   uint32 size;
   if (!Send(new GpuCommandBufferMsg_GetTransferBuffer(route_id_,
                                                       id,
                                                       &handle,
                                                       &size))) {
     return Buffer();
   }
 
   // Cache the transfer buffer shared memory object client side.
   base::SharedMemory* shared_memory = new base::SharedMemory(handle, false);
@@ skipping 202 matching lines @@
 
 void CommandBufferProxyImpl::SetOnConsoleMessageCallback(
     const GpuConsoleMessageCallback& callback) {
   console_message_callback_ = callback;
 }
 
 void CommandBufferProxyImpl::TryUpdateState() {
   if (last_state_.error == gpu::error::kNoError)
     shared_state_->Read(&last_state_);
 }