Make output path to render_pictures optional
Review URL: https://codereview.appspot.com/6779049

git-svn-id: http://skia.googlecode.com/svn/trunk@6136 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tools/PictureRenderer.h b/tools/PictureRenderer.h
index 4829e1d..5d32203 100644
--- a/tools/PictureRenderer.h
+++ b/tools/PictureRenderer.h
@@ -50,7 +50,8 @@
      * If path is non-null, subclass implementations should call write().
      * @param path If non-null, also write the output to the file specified by path. path should
      *             have no extension; it will be added by write().
-     * @return bool True if path is non-null and the output is successfully written to a file.
+     * @return bool True if rendering succeeded and, if path is non-null, the output was
+     *             successfully written to a file.
      */
     virtual bool render(const SkString* path) = 0;