Replace a lot of 'static const' with 'constexpr' or 'const'.

gm/composeshader.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gm.h"
 
 #include "SkCanvas.h"
@@ skipping 192 matching lines @@
             canvas->translate(0, r.height() + 5);
         }
     }
 
 private:
     /** This determines the length and width of the bitmaps used in the ComposeShaders.  Values
      *  above 20 may cause an SkASSERT to fail in SkSmallAllocator. However, larger values will
      *  work in a release build.  You can change this parameter and then compile a release build
      *  to have this GM draw larger bitmaps for easier visual inspection.
      */
-    static const int squareLength = 20;
+    static constexpr int squareLength = 20;
 
     SkBitmap fColorBitmap;
     SkBitmap fAlpha8Bitmap;
     sk_sp<SkShader> fColorBitmapShader;
     sk_sp<SkShader> fAlpha8BitmapShader;
     sk_sp<SkShader> fLinearGradientShader;
 
     typedef GM INHERITED;
 };
 
@@ skipping 33 matching lines @@
     paint.setShader(
         SkShader::MakeComposeShader(skMaskShader, skSrcShader, dstInMode));
     canvas->drawRect(r, paint);
 }
 
 //////////////////////////////////////////////////////////////////////////////
 
 DEF_GM( return new ComposeShaderGM; )
 DEF_GM( return new ComposeShaderAlphaGM; )
 DEF_GM( return new ComposeShaderBitmapGM; )