Revert of remove (dumb) canvas::NewRaster, and rename surface::NewRasterPMColor to N32Premul

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 "SkCanvasDrawable.h"
 #include "SkCanvasPriv.h"
@@ skipping 2511 matching lines @@
         case kRGB_565_SkColorType:
         case kN32_SkColorType:
             break;
         default:
             return false;
     }
 
     return true;
 }
 
+SkCanvas* SkCanvas::NewRaster(const SkImageInfo& info) {
+    if (!supported_for_raster_canvas(info)) {
+        return NULL;
+    }
+
+    SkBitmap bitmap;
+    if (!bitmap.tryAllocPixels(info)) {
+        return NULL;
+    }
+
+    // should this functionality be moved into allocPixels()?
+    if (!bitmap.info().isOpaque()) {
+        bitmap.eraseColor(0);
+    }
+    return SkNEW_ARGS(SkCanvas, (bitmap));
+}
+
 SkCanvas* SkCanvas::NewRasterDirect(const SkImageInfo& info, void* pixels, size_t rowBytes) {
     if (!supported_for_raster_canvas(info)) {
         return NULL;
     }
 
     SkBitmap bitmap;
     if (!bitmap.installPixels(info, pixels, rowBytes)) {
         return NULL;
     }
     return SkNEW_ARGS(SkCanvas, (bitmap));
@@ skipping 17 matching lines @@
     }
 
     if (matrix) {
         canvas->concat(*matrix);
     }
 }
 
 SkAutoCanvasMatrixPaint::~SkAutoCanvasMatrixPaint() {
     fCanvas->restoreToCount(fSaveCount);
 }