make gm background colors 565 compatible

gm/gradient_matrix.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCanvas.h"
 #include "SkColor.h"
 #include "SkGradientShader.h"
@@ skipping 98 matching lines @@
         ptsArray++;
     }
     canvas->restore();
 }
 
 namespace skiagm {
 
 class GradientMatrixGM : public GM {
 public:
     GradientMatrixGM() {
-        this->setBGColor(0xFFDDDDDD);
+        this->setBGColor(sk_tool_utils::color_to_565(0xFFDDDDDD));
     }
 
 protected:
 
     SkString onShortName() override {
         return SkString("gradient_matrix");
     }
 
     SkISize onISize() override {
         return SkISize::Make(800, 800);
     }
 
     void onDraw(SkCanvas* canvas) override {
         draw_gradients(canvas, &make_linear_gradient,
                       linearPts, SK_ARRAY_COUNT(linearPts));
 
         canvas->translate(0, TESTGRID_Y);
 
         draw_gradients(canvas, &make_radial_gradient,
                       radialPts, SK_ARRAY_COUNT(radialPts));
     }
 
 private:
     typedef GM INHERITED;
 };
 
 DEF_GM( return new GradientMatrixGM; )
 }