Pass and return GrColor4h by const& when possible

Bug: skia:
Change-Id: I8486d0631e4723f1a457a607bc21abd2581133d8
Reviewed-on: https://skia-review.googlesource.com/c/166562
Commit-Queue: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
Auto-Submit: Brian Osman <brianosman@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
diff --git a/src/gpu/ops/GrAAStrokeRectOp.cpp b/src/gpu/ops/GrAAStrokeRectOp.cpp
index 92f0c62..458c705 100644
--- a/src/gpu/ops/GrAAStrokeRectOp.cpp
+++ b/src/gpu/ops/GrAAStrokeRectOp.cpp
@@ -133,8 +133,8 @@
                                                      devOutside, devInside);
     }
 
-    AAStrokeRectOp(const Helper::MakeArgs& helperArgs, GrColor4h color, const SkMatrix& viewMatrix,
-                   const SkRect& devOutside, const SkRect& devInside)
+    AAStrokeRectOp(const Helper::MakeArgs& helperArgs, const GrColor4h& color,
+                   const SkMatrix& viewMatrix, const SkRect& devOutside, const SkRect& devInside)
             : INHERITED(ClassID())
             , fHelper(helperArgs, GrAAType::kCoverage)
             , fViewMatrix(viewMatrix) {
@@ -159,8 +159,9 @@
                                                      stroke, isMiter);
     }
 
-    AAStrokeRectOp(const Helper::MakeArgs& helperArgs, GrColor4h color, const SkMatrix& viewMatrix,
-                   const SkRect& rect, const SkStrokeRec& stroke, bool isMiter)
+    AAStrokeRectOp(const Helper::MakeArgs& helperArgs, const GrColor4h& color,
+                   const SkMatrix& viewMatrix, const SkRect& rect, const SkStrokeRec& stroke,
+                   bool isMiter)
             : INHERITED(ClassID())
             , fHelper(helperArgs, GrAAType::kCoverage)
             , fViewMatrix(viewMatrix) {