unsigned -> int for counts and indices in picture-related code

src/core/SkBBoxHierarchy.h

Index: src/core/SkBBoxHierarchy.h
diff --git a/src/core/SkBBoxHierarchy.h b/src/core/SkBBoxHierarchy.h
index 69fb4fd9822b1a56a927685d3634074ab29b35a3..795406f61b2c9cd8a8f240edea43424e092d0810 100644
--- a/src/core/SkBBoxHierarchy.h
+++ b/src/core/SkBBoxHierarchy.h
@@ -30,14 +30,14 @@ public:
     /**
      * Populate results with the indices of bounding boxes interesecting that query.
      */
-    virtual void search(const SkRect& query, SkTDArray<unsigned>* results) const = 0;
+    virtual void search(const SkRect& query, SkTDArray<int>* results) const = 0;
 
     virtual size_t bytesUsed() const = 0;
 
     // Get the root bound.
     virtual SkRect getRootBound() const = 0;
 
-    
+
 private:
     typedef SkRefCnt INHERITED;
 };