Further clean up pepper's use of SharedMemory.

ppapi/proxy/proxy_channel.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 "ppapi/proxy/proxy_channel.h"
 
 #include "base/logging.h"
 #include "ipc/ipc_platform_file.h"
 #include "ipc/ipc_test_sink.h"
 
@@ skipping 58 matching lines @@
     }
     return IPC::InvalidPlatformFileForTransit();
   }
   DCHECK(peer_pid_ != base::kNullProcessId);
   return delegate_->ShareHandleWithRemote(handle, peer_pid_,
                                           should_close_source);
 }
 
 base::SharedMemoryHandle ProxyChannel::ShareSharedMemoryHandleWithRemote(
     const base::SharedMemoryHandle& handle) {
-#if defined(OS_POSIX)
-  return ShareHandleWithRemote(handle.fd, false);
-#elif defined(OS_WIN)
-  return ShareHandleWithRemote(handle, false);
-#else
-#error Not implemented.
-#endif
+  if (!channel_.get())
+    return base::SharedMemory::NULLHandle();
+
+  DCHECK(peer_pid_ != base::kNullProcessId);
+  return delegate_->ShareSharedMemoryHandleWithRemote(handle, peer_pid_);
 }
 
 bool ProxyChannel::Send(IPC::Message* msg) {
   if (test_sink_)
     return test_sink_->Send(msg);
   if (channel_.get())
     return channel_->Send(msg);
 
   // Remote side crashed, drop this message.
   delete msg;
   return false;
 }
 
 }  // namespace proxy
 }  // namespace ppapi