Minor clean up related to blur mask filters

This is the non-substantive portion of: https://codereview.chromium.org/2201133002/ (Implement GPU occluded blur mask filter)

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2214163003

Review-Url: https://codereview.chromium.org/2214163003
diff --git a/src/gpu/SkGpuDevice.cpp b/src/gpu/SkGpuDevice.cpp
index b1c6407..cd34b1f 100644
--- a/src/gpu/SkGpuDevice.cpp
+++ b/src/gpu/SkGpuDevice.cpp
@@ -407,7 +407,7 @@
 
 ///////////////////////////////////////////////////////////////////////////////
 
-void SkGpuDevice::drawRRect(const SkDraw& draw, const SkRRect& rect,
+void SkGpuDevice::drawRRect(const SkDraw& draw, const SkRRect& rrect,
                             const SkPaint& paint) {
     ASSERT_SINGLE_OWNER
     GR_CREATE_TRACE_MARKER_CONTEXT("SkGpuDevice", "drawRRect", fContext);
@@ -423,7 +423,7 @@
         // try to hit the fast path for drawing filtered round rects
 
         SkRRect devRRect;
-        if (rect.transform(*draw.fMatrix, &devRRect)) {
+        if (rrect.transform(*draw.fMatrix, &devRRect)) {
             if (devRRect.allCornersCircular()) {
                 SkRect maskRect;
                 if (paint.getMaskFilter()->canFilterMaskGPU(devRRect,
@@ -457,7 +457,7 @@
         // A path effect will presumably transform this rrect into something else.
         SkPath path;
         path.setIsVolatile(true);
-        path.addRRect(rect);
+        path.addRRect(rrect);
         GrBlurUtils::drawPathWithMaskFilter(fContext, fDrawContext.get(),
                                             fClip, path, paint,
                                             *draw.fMatrix, nullptr,
@@ -467,7 +467,7 @@
 
     SkASSERT(!style.pathEffect());
 
-    fDrawContext->drawRRect(fClip, grPaint, *draw.fMatrix, rect, style);
+    fDrawContext->drawRRect(fClip, grPaint, *draw.fMatrix, rrect, style);
 }