Refactoring: Make IPC::Channel::TakeClientFileDescriptor() a ScopedFD.

ppapi/proxy/proxy_channel.cc

Index: ppapi/proxy/proxy_channel.cc
diff --git a/ppapi/proxy/proxy_channel.cc b/ppapi/proxy/proxy_channel.cc
index 7a7dfaa469e086a6c4fba7bc8010ee2123eeb26f..45c2a77955aabf3a05afd22e917491c99f245c80 100644
--- a/ppapi/proxy/proxy_channel.cc
+++ b/ppapi/proxy/proxy_channel.cc
@@ -53,7 +53,7 @@ void ProxyChannel::OnChannelError() {
 }
 
 #if defined(OS_POSIX) && !defined(OS_NACL)
-int ProxyChannel::TakeRendererFD() {
+base::ScopedFD ProxyChannel::TakeRendererFD() {
   DCHECK(channel());
   return channel()->TakeClientFileDescriptor();
 }