Remove unused matrix param from GrContext/GrDrawTarget rect drawing functions.

src/gpu/GrDefaultPathRenderer.cpp

Index: src/gpu/GrDefaultPathRenderer.cpp
diff --git a/src/gpu/GrDefaultPathRenderer.cpp b/src/gpu/GrDefaultPathRenderer.cpp
index bd9b1ea16a38dfc948e54f8af60bd4bebda1f9d7..dd6ae9d02514f80e6c2708d0053e3972be8584b4 100644
--- a/src/gpu/GrDefaultPathRenderer.cpp
+++ b/src/gpu/GrDefaultPathRenderer.cpp
@@ -491,7 +491,7 @@ bool GrDefaultPathRenderer::internalDrawPath(const SkPath& path,
                 bounds = path.getBounds();
             }
             GrDrawTarget::AutoGeometryAndStatePush agasp(target, GrDrawTarget::kPreserve_ASRInit);
-            target->drawSimpleRect(bounds, NULL);
+            target->drawSimpleRect(bounds);
         } else {
             if (passCount > 1) {
                 drawState->enableState(GrDrawState::kNoColorWrites_StateBit);