Fix off-by-one error in RasterShape of CSS shapes

LayoutTests/fast/shapes/shape-outside-floats/shape-outside-insert-svg-shape.html

Index: LayoutTests/fast/shapes/shape-outside-floats/shape-outside-insert-svg-shape.html
diff --git a/LayoutTests/fast/shapes/shape-outside-floats/shape-outside-insert-svg-shape.html b/LayoutTests/fast/shapes/shape-outside-floats/shape-outside-insert-svg-shape.html
index d8e721398075f473d66dba124e2da65de6525ce2..9789613e6a5e33549029ef6586ed0cbb1e1c6ae7 100644
--- a/LayoutTests/fast/shapes/shape-outside-floats/shape-outside-insert-svg-shape.html
+++ b/LayoutTests/fast/shapes/shape-outside-floats/shape-outside-insert-svg-shape.html
@@ -10,7 +10,7 @@
     width: 100px;
     height: 100px;
     float: left;
-    shape-outside: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='100px' height='100px'><rect x='0' y='50' width='49' height='49' fill='blue'/></svg>");
+    shape-outside: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='100px' height='100px'><rect x='0' y='50' width='50' height='50' fill='blue'/></svg>");
 }
 </style>
 <script>
@@ -28,4 +28,3 @@ window.onload = function() {
 </div>
 </body>
 </html>
-