base: Use stl utilities from the base namespace

base/scoped_observer.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 BASE_SCOPED_OBSERVER_H_
 #define BASE_SCOPED_OBSERVER_H_
 
 #include <stddef.h>
 
 #include <algorithm>
@@ skipping 29 matching lines @@
     source->RemoveObserver(observer_);
   }
 
   void RemoveAll() {
     for (size_t i = 0; i < sources_.size(); ++i)
       sources_[i]->RemoveObserver(observer_);
     sources_.clear();
   }
 
   bool IsObserving(Source* source) const {
-    return ContainsValue(sources_, source);
+    return base::ContainsValue(sources_, source);
   }
 
   bool IsObservingSources() const { return !sources_.empty(); }
 
  private:
   Observer* observer_;
 
   std::vector<Source*> sources_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedObserver);
 };
 
 #endif  // BASE_SCOPED_OBSERVER_H_