add interactive xfer sample

BUG=skia:
TBR=

Review URL: https://codereview.chromium.org/1323223004
diff --git a/src/views/SkView.cpp b/src/views/SkView.cpp
index 249737a..ec75d61 100644
--- a/src/views/SkView.cpp
+++ b/src/views/SkView.cpp
@@ -378,12 +378,16 @@
         F2BIter    iter(this);
         SkView*    child;
 
-        while ((child = iter.next()) != nullptr)
-        {
+        while ((child = iter.next()) != nullptr) {
             SkPoint p;
+#if 0
             if (!child->globalToLocal(x, y, &p)) {
                 continue;
             }
+#else
+            // the above seems broken, so just respecting fLoc for now <reed>
+            p.set(x - child->fLoc.x(), y - child->fLoc.y());
+#endif
 
             Click* click = child->findClickHandler(p.fX, p.fY, modi);