Make filters use SkImage instead of SkBitmap

src/effects/SkDropShadowImageFilter.cpp

Index: src/effects/SkDropShadowImageFilter.cpp
diff --git a/src/effects/SkDropShadowImageFilter.cpp b/src/effects/SkDropShadowImageFilter.cpp
index c453411d8064b4901bdca1f49d13cabdcd21a2fd..3dd9081561125ce2f7a80edc8e0ae0dda882ed2e 100644
--- a/src/effects/SkDropShadowImageFilter.cpp
+++ b/src/effects/SkDropShadowImageFilter.cpp
@@ -53,13 +53,14 @@ void SkDropShadowImageFilter::flatten(SkWriteBuffer& buffer) const {
     buffer.writeInt(static_cast<int>(fShadowMode));
 }
 
-bool SkDropShadowImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& source,
+bool SkDropShadowImageFilter::onFilterImage(Proxy* proxy, const SkImage* source,
                                             const Context& ctx,
-                                            SkBitmap* result, SkIPoint* offset) const
+                                            SkAutoTUnref<const SkImage>& result,
+                                            SkIPoint* offset) const
 {
-    SkBitmap src = source;
+    SkAutoTUnref<const SkImage> src(SkRef(source));
     SkIPoint srcOffset = SkIPoint::Make(0, 0);
-    if (getInput(0) && !getInput(0)->filterImage(proxy, source, ctx, &src, &srcOffset))
+    if (getInput(0) && !getInput(0)->filterImage(proxy, source, ctx, src, &srcOffset))
         return false;
 
     SkIRect bounds;
@@ -88,11 +89,17 @@ bool SkDropShadowImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& source
     ctx.ctm().mapVectors(&offsetVec, 1);
     canvas.translate(SkIntToScalar(srcOffset.fX - bounds.fLeft),
                      SkIntToScalar(srcOffset.fY - bounds.fTop));
-    canvas.drawBitmap(src, offsetVec.fX, offsetVec.fY, &paint);
+    canvas.drawImage(src, offsetVec.fX, offsetVec.fY, &paint);
     if (fShadowMode == kDrawShadowAndForeground_ShadowMode) {
-        canvas.drawBitmap(src, 0, 0);
+        canvas.drawImage(src, 0, 0);
     }
-    *result = device->accessBitmap(false);
+
+    SkImage* image = device->newImageSnapshot();
+    if (NULL == image) {
+        return false;
+    }
+    result.reset(image);
+
     offset->fX = bounds.fLeft;
     offset->fY = bounds.fTop;
     return true;