improvements of the FPS counter in the HUDLayer

cc/heads_up_display_layer_impl.h

 // Copyright 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 CCHeadsUpDisplayLayerImpl_h
 #define CCHeadsUpDisplayLayerImpl_h
 
 #include "CCFontAtlas.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/time.h"
 #include "cc/layer_impl.h"
 #include "cc/scoped_texture.h"
 
 class SkCanvas;
+class SkPaint;
+class SkRect;
 
 namespace cc {
 
 class DebugRectHistory;
 class FontAtlas;
 class FrameRateCounter;
 
 class HeadsUpDisplayLayerImpl : public LayerImpl {
 public:
     static scoped_ptr<HeadsUpDisplayLayerImpl> create(int id)
@@ skipping 12 matching lines @@
     virtual void didLoseContext() OVERRIDE;
 
     virtual bool layerIsAlwaysDamaged() const OVERRIDE;
 
 private:
     explicit HeadsUpDisplayLayerImpl(int);
 
     virtual const char* layerTypeAsString() const OVERRIDE;
 
     void drawHudContents(SkCanvas*);
-    void drawFPSCounter(SkCanvas*, FrameRateCounter*, int top, int height);
-    void drawFPSCounterText(SkCanvas*, FrameRateCounter*, int top, int width, int height);
+    int drawFPSCounter(SkCanvas*, FrameRateCounter*);
+    void drawFPSCounterText(SkCanvas*, SkPaint&, FrameRateCounter*, SkRect);
+    void drawFPSCounterGraph(SkCanvas*, SkPaint&, FrameRateCounter*, SkRect);
     void drawDebugRects(SkCanvas*, DebugRectHistory*);
 
     scoped_ptr<FontAtlas> m_fontAtlas;
     scoped_ptr<ScopedTexture> m_hudTexture;
     scoped_ptr<SkCanvas> m_hudCanvas;
+
+    double m_averageFPS;
+    double m_stdDeviation;
+
+    base::TimeTicks textUpdateTime;
 };
 
 }  // namespace cc
 
 #endif // CCHeadsUpDisplayLayerImpl_h