Implement support for a Context parameter in image filters

src/effects/SkPictureImageFilter.cpp

 /*
  * Copyright 2013 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 "SkPictureImageFilter.h"
 #include "SkDevice.h"
 #include "SkCanvas.h"
@@ skipping 40 matching lines @@
     buffer.writeBool(hasPicture);
     if (hasPicture) {
         fPicture->flatten(buffer);
     }
 #else
     buffer.writeBool(false);
 #endif
     buffer.writeRect(fCropRect);
 }
 
-bool SkPictureImageFilter::onFilterImage(Proxy* proxy, const SkBitmap&, const SkMatrix& matrix,
-                                   SkBitmap* result, SkIPoint* offset) const {
+bool SkPictureImageFilter::onFilterImage(Proxy* proxy, const SkBitmap&, const Context& ctx,
+                                         SkBitmap* result, SkIPoint* offset) const {
     if (!fPicture) {
         offset->fX = offset->fY = 0;
         return true;
     }
 
     SkRect floatBounds;
     SkIRect bounds;
-    matrix.mapRect(&floatBounds, fCropRect);
+    ctx.ctm().mapRect(&floatBounds, fCropRect);
     floatBounds.roundOut(&bounds);
 
     if (bounds.isEmpty()) {
         offset->fX = offset->fY = 0;
         return true;
     }
 
     SkAutoTUnref<SkBaseDevice> device(proxy->createDevice(bounds.width(), bounds.height()));
     if (NULL == device.get()) {
         return false;
     }
 
     SkCanvas canvas(device.get());
     SkPaint paint;
 
     canvas.translate(-SkIntToScalar(bounds.fLeft), -SkIntToScalar(bounds.fTop));
-    canvas.concat(matrix);
+    canvas.concat(ctx.ctm());
     canvas.drawPicture(*fPicture);
 
     *result = device.get()->accessBitmap(false);
     offset->fX = bounds.fLeft;
     offset->fY = bounds.fTop;
     return true;
 }