Image filters: change applyCropRect() to take a src rect.

src/effects/SkXfermodeImageFilter.cpp

Index: src/effects/SkXfermodeImageFilter.cpp
diff --git a/src/effects/SkXfermodeImageFilter.cpp b/src/effects/SkXfermodeImageFilter.cpp
index fbceedb0dd6e0b53e605660a19384a1b48ad234d..3f702e69c4ccfa125acd1b211259f01745474c11 100644
--- a/src/effects/SkXfermodeImageFilter.cpp
+++ b/src/effects/SkXfermodeImageFilter.cpp
@@ -57,11 +57,15 @@ bool SkXfermodeImageFilter::onFilterImage(Proxy* proxy,
     }
 
     SkIRect bounds, foregroundBounds;
-    if (!applyCropRect(ctx, foreground, foregroundOffset, &foregroundBounds)) {
+    SkIRect foregroundSrcBounds = foreground.bounds();
+    foregroundSrcBounds.offset(foregroundOffset);
+    if (!applyCropRect(ctx, foregroundSrcBounds, &foregroundBounds)) {
         foregroundBounds.setEmpty();
         foreground.reset();
     }
-    if (!applyCropRect(ctx, background, backgroundOffset, &bounds)) {
+    SkIRect backgroundSrcBounds = background.bounds();
+    backgroundSrcBounds.offset(backgroundOffset);
+    if (!applyCropRect(ctx, backgroundSrcBounds, &bounds)) {
         bounds.setEmpty();
         background.reset();
     }