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

src/gpu/gl/GrGpuGL.cpp

Index: src/gpu/gl/GrGpuGL.cpp
diff --git a/src/gpu/gl/GrGpuGL.cpp b/src/gpu/gl/GrGpuGL.cpp
index 8982785b3e31f5eefce491a9102af2b3c63bed8e..adcddcc108daaffa1f60de7bab0d859fc61ac743 100644
--- a/src/gpu/gl/GrGpuGL.cpp
+++ b/src/gpu/gl/GrGpuGL.cpp
@@ -1935,7 +1935,7 @@ void GrGpuGL::onGpuDrawPath(const GrPath* path, SkPath::FillType fill) {
             avmr.setIdentity(drawState);
         }
 
-        this->drawSimpleRect(bounds, NULL);
+        this->drawSimpleRect(bounds);
     }
 }
 
@@ -2012,7 +2012,7 @@ void GrGpuGL::onGpuDrawPaths(const GrPathRange* pathRange,
             avmr.setIdentity(drawState);
         }
 
-        this->drawSimpleRect(bounds, NULL);
+        this->drawSimpleRect(bounds);
     }
 }