Split testing_pref_service.h/.cc into two parts, generic vs. Chrome-specific.

chrome/browser/prefs/session_startup_pref_unittest.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 "chrome/browser/prefs/pref_registry_syncable.h"
 #include "chrome/browser/prefs/session_startup_pref.h"
 #include "chrome/common/pref_names.h"
-#include "chrome/test/base/testing_pref_service.h"
+#include "chrome/test/base/testing_pref_service_syncable.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 #if defined(OS_MACOSX)
 #include "chrome/browser/ui/cocoa/window_restore_utils.h"
 #endif
 
 // Unit tests for SessionStartupPref.
 class SessionStartupPrefTest : public testing::Test {
  public:
@@ skipping 165 matching lines @@
 
   // Trigger the migration.
   SessionStartupPref pref = SessionStartupPref::GetStartupPref(
       pref_service_.get());
 
   // The pref is now explicit.
   EXPECT_EQ(SessionStartupPref::LAST, pref.type);
   EXPECT_FALSE(SessionStartupPref::TypeIsDefault(pref_service_.get()));
 }
 #endif