add /img/n/m endpoint to skiaserve

tools/debugger/SkDebugCanvas.h

 
 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SKDEBUGCANVAS_H_
@@ skipping 50 matching lines @@
     /**
         Executes all draw calls to the canvas.
         @param canvas  The canvas being drawn to
      */
     void draw(SkCanvas* canvas);
 
     /**
         Executes the draw calls up to the specified index.
         @param canvas  The canvas being drawn to
         @param index  The index of the final command being executed
+        @param m an optional Mth gpu batch to highlight, or -1
      */
-    void drawTo(SkCanvas* canvas, int index);
+    void drawTo(SkCanvas* canvas, int index, int m = -1);
 
     /**
         Returns the most recently calculated transformation matrix
      */
     const SkMatrix& getCurrentMatrix() {
         return fMatrix;
     }
 
     /**
         Returns the most recently calculated clip
@@ skipping 199 matching lines @@
     void outputPoints(const SkPoint* pts, int count);
     void outputPointsCommon(const SkPoint* pts, int count);
     void outputScalar(SkScalar num);
 
     void updatePaintFilterCanvas();
 
     typedef SkCanvas INHERITED;
 };
 
 #endif