change SkDraw and all Blitters to use pixmap instead of bitmap

src/core/SkCanvas.cpp

 /*
  * Copyright 2008 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.
  */
 
 #include "SkCanvas.h"
 #include "SkCanvasPriv.h"
 #include "SkBitmapDevice.h"
@@ skipping 253 matching lines @@
             }
         }
 
         const DeviceCM* rec = fCurrLayer;
         if (rec && rec->fDevice) {
 
             fMatrix = rec->fMatrix;
             fClip   = &((SkRasterClip*)&rec->fClip)->forceGetBW();
             fRC     = &rec->fClip;
             fDevice = rec->fDevice;
-            fBitmap = &fDevice->accessBitmap(true);
+            if (!fDevice->accessPixels(&fDst)) {
+                fDst.reset(fDevice->imageInfo(), NULL, 0);
+            }
             fPaint  = rec->fPaint;
             SkDEBUGCODE(this->validate();)
 
             fCurrLayer = rec->fNext;
             // fCurrLayer may be NULL now
 
             return true;
         }
         return false;
     }
@@ skipping 2426 matching lines @@
     }
 
     if (matrix) {
         canvas->concat(*matrix);
     }
 }
 
 SkAutoCanvasMatrixPaint::~SkAutoCanvasMatrixPaint() {
     fCanvas->restoreToCount(fSaveCount);
 }