Implement bounds traversals for tile and matrix convolution filters.

src/effects/SkTileImageFilter.cpp

Index: src/effects/SkTileImageFilter.cpp
diff --git a/src/effects/SkTileImageFilter.cpp b/src/effects/SkTileImageFilter.cpp
index f3bad76345232436f96318f67b8ed2bca10c6856..73c0a581e98e5ae57c7e3cbcd7c92195a6d33a4c 100644
--- a/src/effects/SkTileImageFilter.cpp
+++ b/src/effects/SkTileImageFilter.cpp
@@ -75,6 +75,17 @@ bool SkTileImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& src,
     return true;
 }
 
+bool SkTileImageFilter::onFilterBounds(const SkIRect& src, const SkMatrix& ctm,
+                                       SkIRect* dst) const {
+    SkRect srcRect;
+    ctm.mapRect(&srcRect, fSrcRect);
+    SkIRect srcIRect;
+    srcRect.roundOut(&srcIRect);
+    srcIRect.join(src);
+    *dst = srcIRect;
+    return true;
+}
+
 SkTileImageFilter::SkTileImageFilter(SkReadBuffer& buffer)
   : INHERITED(1, buffer) {
     buffer.readRect(&fSrcRect);