Make RTree handle the case where the playback canvas has empty clip bounds

src/core/SkRecordDraw.cpp

Index: src/core/SkRecordDraw.cpp
diff --git a/src/core/SkRecordDraw.cpp b/src/core/SkRecordDraw.cpp
index 5981245c018700e8ed969e7abc75e1d76c63b7ba..d7413e81e10b7d15292ce3943959ebc3c547da0f 100644
--- a/src/core/SkRecordDraw.cpp
+++ b/src/core/SkRecordDraw.cpp
@@ -20,8 +20,9 @@ void SkRecordDraw(const SkRecord& record,
         // is not necessarily in that same space.  getClipBounds() returns us
         // this canvas' clip bounds transformed back into identity space, which
         // lets us query the BBH.
-        SkRect query = { 0, 0, 0, 0 };
-        (void)canvas->getClipBounds(&query);
+        SkRect query;
+        if (!canvas->getClipBounds(&query))

[mtklein, 2014/10/28 17:29:43]

{} ?

+            return;
 
         SkTDArray<unsigned> ops;
         bbh->search(query, &ops);