Implement SkPictureImageFilter bounds computation.

SkPictureImageFilter::onFilterBounds() was unimplemented, causing
incorrect results for SVG filters and impl-side painting (see Chrome
bug https://code.google.com/p/chromium/issues/detail?id=375162).

BUG=skia:
R=reed@google.com

Review URL: https://codereview.chromium.org/306733003

git-svn-id: http://skia.googlecode.com/svn/trunk/include@15003 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/effects/SkPictureImageFilter.h b/effects/SkPictureImageFilter.h
index 0a72f71..fe07215 100644
--- a/effects/SkPictureImageFilter.h
+++ b/effects/SkPictureImageFilter.h
@@ -44,6 +44,8 @@
     virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
     virtual bool onFilterImage(Proxy*, const SkBitmap& src, const Context&,
                                SkBitmap* result, SkIPoint* offset) const SK_OVERRIDE;
+    virtual bool onFilterBounds(const SkIRect& src, const SkMatrix&,
+                                SkIRect* dst) const SK_OVERRIDE;
 
 private:
     SkPicture* fPicture;