Make SystemMonitor not a Singleton and move it out of base

chrome/browser/tabs/tab_strip_model_unittest.cc

 // Copyright (c) 2006-2008 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 "app/system_monitor.h"
 #include "base/file_util.h"
 #include "base/path_service.h"
 #include "base/string_util.h"
 #include "base/stl_util-inl.h"
 #include "chrome/browser/dom_ui/new_tab_ui.h"
 #include "chrome/browser/profile.h"
 #include "chrome/browser/profile_manager.h"
 #include "chrome/browser/renderer_host/test/test_render_view_host.h"
 #include "chrome/browser/tab_contents/navigation_controller.h"
 #include "chrome/browser/tab_contents/navigation_entry.h"
@@ skipping 129 matching lines @@
 
  private:
   PropertyAccessor<int>* GetIDAccessor() {
     static PropertyAccessor<int> accessor;
     return &accessor;
   }
 
   std::wstring test_dir_;
   std::wstring profile_path_;
   std::map<TabContents*, int> foo_;
+
+  // ProfileManager requires a SystemMonitor.
+  SystemMonitor system_monitor;
+
   ProfileManager pm_;
 };
 
 class MockTabStripModelObserver : public TabStripModelObserver {
  public:
   MockTabStripModelObserver() : empty_(true) {}
   ~MockTabStripModelObserver() {
     STLDeleteContainerPointers(states_.begin(), states_.end());
   }
 
@@ skipping 1364 matching lines @@
     tabstrip.AppendTabContents(contents2, true);
 
     tabstrip.CloseTabContentsAt(1);
     EXPECT_FALSE(contents1->process()->fast_shutdown_started());
     EXPECT_EQ(1, tabstrip.count());
 
     tabstrip.CloseAllTabs();
     EXPECT_TRUE(tabstrip.empty());
   }
 }