Always use both a color and coverage attribute in GrAARectRenderer.

R=robertphillips@google.com

Author: bsalomon@google.com

Review URL: https://codereview.chromium.org/435743002
diff --git a/src/gpu/GrClipMaskManager.cpp b/src/gpu/GrClipMaskManager.cpp
index edd4454..0f79402 100644
--- a/src/gpu/GrClipMaskManager.cpp
+++ b/src/gpu/GrClipMaskManager.cpp
@@ -404,8 +404,7 @@
                                                               fGpu,
                                                               element->getRect(),
                                                               SkMatrix::I(),
-                                                              element->getRect(),
-                                                              false);
+                                                              element->getRect());
             } else {
                 fGpu->drawSimpleRect(element->getRect());
             }