Move lots of GMock stuff out of line.

chrome/browser/prefs/pref_observer_mock.cc

+// Copyright (c) 2011 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_observer_mock.h"
+
+PrefObserverMock::PrefObserverMock() {}
+
+PrefObserverMock::~PrefObserverMock() {}
+
+void PrefObserverMock::Expect(const PrefService* prefs,
+                              const std::string& pref_name,
+                              const Value* value) {
+  EXPECT_CALL(*this, Observe(NotificationType(NotificationType::PREF_CHANGED),
+                             Source<PrefService>(prefs),
+                             Property(&Details<std::string>::ptr,
+                                      Pointee(pref_name))))
+      .With(PrefValueMatches(prefs, pref_name, value));
+}