Make enabling static rect VB configurable by user config file.

git-svn-id: http://skia.googlecode.com/svn/trunk@753 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/include/GrUserConfig.h b/gpu/include/GrUserConfig.h
index 2d46b9f..3484760 100644
--- a/gpu/include/GrUserConfig.h
+++ b/gpu/include/GrUserConfig.h
@@ -51,6 +51,14 @@
  */
 //#define GR_GL_LOG_CALLS 1
 
+/*
+ * When drawing rects this causes Ganesh to use a vertex buffer containing
+ * a unit square that is positioned by a matrix. Enable on systems where
+ * emitting per-rect-draw verts is more expensive than constant/matrix
+ * updates. Defaults to 0.
+ */
+//#define GR_STATIC_RECT_VB 1
+
 ///////////////////////////////////////////////////////////////////////////////
 /*
  *  temporary flags (may go away soon)