Fix rtree bench

R=caryclark@google.com

Review URL: https://codereview.chromium.org/23609009

git-svn-id: http://skia.googlecode.com/svn/trunk@11041 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/bench/RTreeBench.cpp b/bench/RTreeBench.cpp
index d017f39..624391c 100644
--- a/bench/RTreeBench.cpp
+++ b/bench/RTreeBench.cpp
@@ -168,16 +168,16 @@
     SkIRect out;
     out.fLeft = index % GRID_WIDTH;
     out.fTop = index / GRID_WIDTH;
-    out.fRight  = 1 + rand.nextU() % (GENERATE_EXTENTS / 3);
-    out.fBottom = 1 + rand.nextU() % (GENERATE_EXTENTS / 3);
+    out.fRight  = fLeft + 1 + rand.nextU() % (GENERATE_EXTENTS / 3);
+    out.fBottom = fTop + 1 + rand.nextU() % (GENERATE_EXTENTS / 3);
     return out;
 }
 static inline SkIRect make_YXordered_rects(SkMWCRandom& rand, int index, int numRects) {
     SkIRect out;
     out.fLeft = index / GRID_WIDTH;
     out.fTop = index % GRID_WIDTH;
-    out.fRight  = 1 + rand.nextU() % (GENERATE_EXTENTS / 3);
-    out.fBottom = 1 + rand.nextU() % (GENERATE_EXTENTS / 3);
+    out.fRight  = fLeft + 1 + rand.nextU() % (GENERATE_EXTENTS / 3);
+    out.fBottom = fTop + 1 + rand.nextU() % (GENERATE_EXTENTS / 3);
     return out;
 }