Change clear() to respect the clip

include/core/SkCanvas.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkCanvas_DEFINED
 #define SkCanvas_DEFINED
 
@@ skipping 601 matching lines @@
         @param mode the mode to apply the color in (defaults to SrcOver)
     */
     void drawARGB(U8CPU a, U8CPU r, U8CPU g, U8CPU b,
                   SkXfermode::Mode mode = SkXfermode::kSrcOver_Mode);
 
     /** Fill the entire canvas' bitmap (restricted to the current clip) with the
         specified color and mode.
         @param color    the color to draw with
         @param mode the mode to apply the color in (defaults to SrcOver)
     */
-    void drawColor(SkColor color,
-                   SkXfermode::Mode mode = SkXfermode::kSrcOver_Mode);
+    void drawColor(SkColor color, SkXfermode::Mode mode = SkXfermode::kSrcOver_Mode);
 
-    /**
-     *  This erases the entire drawing surface to the specified color,
-     *  irrespective of the clip. It does not blend with the previous pixels,
-     *  but always overwrites them.
-     *
-     *  It is roughly equivalent to the following:
-     *      canvas.save();
-     *      canvas.clipRect(hugeRect, kReplace_Op);
-     *      paint.setColor(color);
-     *      paint.setXfermodeMode(kSrc_Mode);
-     *      canvas.drawPaint(paint);
-     *      canvas.restore();
-     *  though it is almost always much more efficient.
-     */
-    virtual void clear(SkColor);
+    // TODO: remove virtual when chrome subclass stop overriding this.
+    virtual void clear(SkColor color) {
+        this->drawColor(color, SkXfermode::kSrc_Mode);
+    }
 
     /**
      * This makes the contents of the canvas undefined. Subsequent calls that
      * require reading the canvas contents will produce undefined results. Examples
      * include blending and readPixels. The actual implementation is backend-
      * dependent and one legal implementation is to do nothing. Like clear(), this
      * ignores the clip.
      *
      * This function should only be called if the caller intends to subsequently
      * draw to the canvas. The canvas may do real work at discard() time in order
@@ skipping 898 matching lines @@
 
 class SkCanvasClipVisitor {
 public:
     virtual ~SkCanvasClipVisitor();
     virtual void clipRect(const SkRect&, SkRegion::Op, bool antialias) = 0;
     virtual void clipRRect(const SkRRect&, SkRegion::Op, bool antialias) = 0;
     virtual void clipPath(const SkPath&, SkRegion::Op, bool antialias) = 0;
 };
 
 #endif