Remove "mixin" from BeginFrameSource/Observer base classes.

cc/scheduler/begin_frame_source.h

 // Copyright 2014 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 CC_SCHEDULER_BEGIN_FRAME_SOURCE_H_
 #define CC_SCHEDULER_BEGIN_FRAME_SOURCE_H_
 
 #include <set>
 #include <string>
 
@@ skipping 42 matching lines @@
   virtual void AsValueInto(base::trace_event::TracedValue* dict) const = 0;
 };
 
 // Simple mix in which implements a BeginFrameObserver which checks the
 // incoming values meet the BeginFrameObserver requirements and implements the
 // required LastUsedBeginFrameArgs behaviour.
 //
 // Users of this mix in should;
 //  - Implement the OnBeginFrameMixInDelegate function.
 //  - Recommended (but not required) to call
-//    BeginFrameObserverMixIn::OnValueInto in their overridden OnValueInto
+//    BeginFrameObserverBase::OnValueInto in their overridden OnValueInto
 //    function.
-class CC_EXPORT BeginFrameObserverMixIn : public BeginFrameObserver {
+class CC_EXPORT BeginFrameObserverBase : public BeginFrameObserver {
  public:
-  BeginFrameObserverMixIn();
+  BeginFrameObserverBase();
 
   // BeginFrameObserver
 
   // Traces |args| and DCHECK |args| satisfies pre-conditions then calls
   // OnBeginFrameMixInDelegate and updates the last_begin_frame_args_ value on
   // true.
   void OnBeginFrame(const BeginFrameArgs& args) override;
   const BeginFrameArgs LastUsedBeginFrameArgs() const override;
 
   // Outputs last_begin_frame_args_
@@ skipping 196 matching lines @@
 
   base::TimeDelta minimum_interval_;
 
   BeginFrameSource* active_source_;
   std::set<BeginFrameSource*> source_list_;
 };
 
 }  // namespace cc
 
 #endif  // CC_SCHEDULER_BEGIN_FRAME_SOURCE_H_