change SkDraw and all Blitters to use pixmap instead of bitmap

bench/CoverageBench.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Benchmark.h"
 #include "SkBitmap.h"
 #include "SkCanvas.h"
 #include "SkColorPriv.h"
 #include "SkDraw.h"
 #include "SkMatrix.h"
 #include "SkPath.h"
 #include "SkRasterClip.h"
 
 class DrawPathBench : public Benchmark {
     SkPaint     fPaint;
     SkString    fName;
     SkPath      fPath;
     SkRasterClip fRC;
-    SkBitmap    fBitmap;
+    SkAutoPixmapStorage fPixmap;
     SkMatrix    fIdentity;
     SkDraw      fDraw;
     bool        fDrawCoverage;
 public:
     DrawPathBench(bool drawCoverage) : fDrawCoverage(drawCoverage) {
         fPaint.setAntiAlias(true);
         fName.printf("draw_coverage_%s", drawCoverage ? "true" : "false");
 
         fPath.moveTo(0, 0);
         fPath.quadTo(500, 0, 500, 500);
         fPath.quadTo(250, 0, 0, 500);
 
-        fBitmap.allocPixels(SkImageInfo::MakeA8(500, 500));
+        fPixmap.alloc(SkImageInfo::MakeA8(500, 500));
 
         fIdentity.setIdentity();
         fRC.setRect(fPath.getBounds().round());
 
-        fDraw.fBitmap   = &fBitmap;
+        fDraw.fDst      = fPixmap;
         fDraw.fMatrix   = &fIdentity;
         fDraw.fClip     = &fRC.bwRgn();
         fDraw.fRC       = &fRC;
     }
 
 protected:
     const char* onGetName() override {
         return fName.c_str();
     }
 
@@ skipping 10 matching lines @@
     }
 
 private:
     typedef Benchmark INHERITED;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 DEF_BENCH( return new DrawPathBench(false) )
 DEF_BENCH( return new DrawPathBench(true) )