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

R=robertphillips@google.com

Author: bsalomon@google.com

Review URL: https://codereview.chromium.org/441623005
diff --git a/src/gpu/GrSoftwarePathRenderer.cpp b/src/gpu/GrSoftwarePathRenderer.cpp
index bca2c66..0d3ef62 100644
--- a/src/gpu/GrSoftwarePathRenderer.cpp
+++ b/src/gpu/GrSoftwarePathRenderer.cpp
@@ -84,22 +84,22 @@
     if (devClipBounds.fTop < devPathBounds.fTop) {
         rect.iset(devClipBounds.fLeft, devClipBounds.fTop,
                   devClipBounds.fRight, devPathBounds.fTop);
-        target->drawSimpleRect(rect, NULL);
+        target->drawSimpleRect(rect);
     }
     if (devClipBounds.fLeft < devPathBounds.fLeft) {
         rect.iset(devClipBounds.fLeft, devPathBounds.fTop,
                   devPathBounds.fLeft, devPathBounds.fBottom);
-        target->drawSimpleRect(rect, NULL);
+        target->drawSimpleRect(rect);
     }
     if (devClipBounds.fRight > devPathBounds.fRight) {
         rect.iset(devPathBounds.fRight, devPathBounds.fTop,
                   devClipBounds.fRight, devPathBounds.fBottom);
-        target->drawSimpleRect(rect, NULL);
+        target->drawSimpleRect(rect);
     }
     if (devClipBounds.fBottom > devPathBounds.fBottom) {
         rect.iset(devClipBounds.fLeft, devPathBounds.fBottom,
                   devClipBounds.fRight, devClipBounds.fBottom);
-        target->drawSimpleRect(rect, NULL);
+        target->drawSimpleRect(rect);
     }
 }