ChannelProxy: Send() from UI thread when ChannelMojo is used.

ipc/ipc_channel.h

 // 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.
 
 #ifndef IPC_IPC_CHANNEL_H_
 #define IPC_IPC_CHANNEL_H_
 
 #include <string>
 
 #if defined(OS_POSIX)
@@ skipping 162 matching lines @@
   // Get its own process id. This value is told to the peer.
   virtual base::ProcessId GetSelfPID() const = 0;
 
   // Overridden from ipc::Sender.
   // Send a message over the Channel to the listener on the other end.
   //
   // |message| must be allocated using operator new.  This object will be
   // deleted once the contents of the Message have been sent.
   virtual bool Send(Message* message) override = 0;
 
+  // True for a particular |Channel| subclass that allows non-IO threads call
+  // |Send()|. The return value must be constant across the lifetime.
+  virtual bool IsSendThreadSafe() const;
+
   // NaCl in Non-SFI mode runs on Linux directly, and the following functions
   // compiled on Linux are also needed. Please see also comments in
   // components/nacl_nonsfi.gyp for more details.
 #if defined(OS_POSIX) && !defined(OS_NACL_SFI)
   // On POSIX an IPC::Channel wraps a socketpair(), this method returns the
   // FD # for the client end of the socket.
   // This method may only be called on the server side of a channel.
   // This method can be called on any thread.
   virtual int GetClientFileDescriptor() const = 0;
 
@@ skipping 37 matching lines @@
 
 #if defined(OS_POSIX)
 // SocketPair() creates a pair of socket FDs suitable for using with
 // IPC::Channel.
 IPC_EXPORT bool SocketPair(int* fd1, int* fd2);
 #endif
 
 }  // namespace IPC
 
 #endif  // IPC_IPC_CHANNEL_H_