fix uninitialized variable warning for vs2012 compilation

content/common/gpu/client/command_buffer_proxy_impl.cc

Index: content/common/gpu/client/command_buffer_proxy_impl.cc
diff --git a/content/common/gpu/client/command_buffer_proxy_impl.cc b/content/common/gpu/client/command_buffer_proxy_impl.cc
index 987ba6fb08e934e3f38d90048fb6416a07b93d32..f261597ac1ec9f051f7509be3ab450fbca2e9d70 100644
--- a/content/common/gpu/client/command_buffer_proxy_impl.cc
+++ b/content/common/gpu/client/command_buffer_proxy_impl.cc
@@ -338,7 +338,7 @@ Buffer CommandBufferProxyImpl::GetTransferBuffer(int32 id) {
 
   // 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,