Mojo: Move PlatformChannelPair to its own files.

mojo/common/test/multiprocess_test_base.h

 // Copyright 2013 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 MOJO_COMMON_TEST_MULTIPROCESS_TEST_BASE_H_
 #define MOJO_COMMON_TEST_MULTIPROCESS_TEST_BASE_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/process/process_handle.h"
 #include "base/test/multiprocess_test.h"
-#include "mojo/system/platform_channel.h"
 #include "testing/multiprocess_func_list.h"
 
 namespace mojo {
+
+namespace system {
+class PlatformChannel;
+class PlatformChannelPair;
+}
+
 namespace test {
 
 class MultiprocessTestBase : public base::MultiProcessTest {
  public:
   MultiprocessTestBase();
   virtual ~MultiprocessTestBase();
 
   virtual void SetUp() OVERRIDE;
   virtual void TearDown() OVERRIDE;
 
@@ skipping 34 matching lines @@
 // code (but see the comment about |WaitForChildShutdown()|).
 #define MOJO_MULTIPROCESS_TEST_CHILD_MAIN(test_child_name) \
     MULTIPROCESS_TEST_MAIN_WITH_SETUP( \
         test_child_name ## TestChildMain, \
         ::mojo::test::MultiprocessTestBase::ChildSetup)
 
 }  // namespace test
 }  // namespace mojo
 
 #endif  // MOJO_COMMON_TEST_MULTIPROCESS_TEST_BASE_H_