Remove virtual clear in PdfViewer's SkNulCanvas

experimental/PdfViewer/SkNulCanvas.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkNulCanvas_DEFINED
 #define SkNulCanvas_DEFINED
 
 #include "SkCanvas.h"
 
 /** \class SkNulCanvas
  *
  *   Nul Canvas is a canvas that does nothing. It is used to measure the perf of just parsing
  *   a pdf, without actually rendering anything.
  *
  */
 class SK_API SkNulCanvas : public SkCanvas {
 public:
     SK_DECLARE_INST_COUNT(SkNulCanvas);
 
     SkNulCanvas() {}
     explicit SkNulCanvas(SkBaseDevice* device) : SkCanvas(device) {}
 
     explicit SkNulCanvas(const SkBitmap& bitmap) : SkCanvas(bitmap) {}
     virtual ~SkNulCanvas() {}
 
     virtual bool isDrawingToLayer() const SK_OVERRIDE {return false;}
-    virtual void clear(SkColor) SK_OVERRIDE {}
     virtual void drawPaint(const SkPaint& paint) SK_OVERRIDE {}
     virtual void drawPoints(PointMode mode, size_t count, const SkPoint pts[],
                             const SkPaint& paint) SK_OVERRIDE {}
     virtual void drawRect(const SkRect& rect, const SkPaint& paint) SK_OVERRIDE {}
     virtual void drawOval(const SkRect& oval, const SkPaint&) SK_OVERRIDE {}
     virtual void drawRRect(const SkRRect& rrect, const SkPaint& paint) SK_OVERRIDE {}
     virtual void drawPath(const SkPath& path, const SkPaint& paint) SK_OVERRIDE {}
     virtual void drawBitmap(const SkBitmap& bitmap, SkScalar left, SkScalar top,
                             const SkPaint* paint = NULL) SK_OVERRIDE {}
     virtual void drawBitmapRectToRect(const SkBitmap& bitmap, const SkRect* src,
@@ skipping 59 matching lines @@
     virtual void onClipPath(const SkPath&, SkRegion::Op, ClipEdgeStyle) SK_OVERRIDE {}
     virtual void onClipRegion(const SkRegion&, SkRegion::Op)  SK_OVERRIDE {}
 
     virtual void onDrawPicture(const SkPicture*, const SkMatrix*, const SkPaint*) SK_OVERRIDE {}
     
 private:
     typedef SkCanvas INHERITED;
 };
 
 #endif  // SkNulCanvas_DEFINED