add optional cull-rect to patheffects, so they can do less work if their results
lie outside of the current clip-bounds (the cull rect).
Review URL: https://codereview.appspot.com/7206044

git-svn-id: http://skia.googlecode.com/svn/trunk@7378 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/SkGpuDevice.cpp b/src/gpu/SkGpuDevice.cpp
index 827fc52..3e20e3b 100644
--- a/src/gpu/SkGpuDevice.cpp
+++ b/src/gpu/SkGpuDevice.cpp
@@ -972,7 +972,9 @@
 
     SkStrokeRec stroke(paint);
     SkPathEffect* pathEffect = paint.getPathEffect();
-    if (pathEffect && pathEffect->filterPath(&effectPath, *pathPtr, &stroke)) {
+    const SkRect* cullRect = NULL;  // TODO: what is our bounds?
+    if (pathEffect && pathEffect->filterPath(&effectPath, *pathPtr, &stroke,
+                                             cullRect)) {
         pathPtr = &effectPath;
     }