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

gm/stroke_rect_shader.cpp

Index: gm/stroke_rect_shader.cpp
diff --git a/gm/stroke_rect_shader.cpp b/gm/stroke_rect_shader.cpp
index 0eb09e9a6f81e4d60a22374081714af0affbf64f..1826f629f6b5c0b9a719378c6bc3000640d9283c 100644
--- a/gm/stroke_rect_shader.cpp
+++ b/gm/stroke_rect_shader.cpp
@@ -14,9 +14,9 @@ namespace skiagm {
 //    bevel, miter, miter-limited-to-bevel, round
 // and as a hairline.
 DEF_SIMPLE_GM(stroke_rect_shader, canvas, 690, 300) {
-    static constexpr SkRect kRect {0, 0, 100, 100};
-    static constexpr SkPoint kPts[] {{kRect.fLeft, kRect.fTop}, {kRect.fRight, kRect.fBottom}};
-    static constexpr SkColor kColors[] {SK_ColorRED, SK_ColorBLUE};
+    constexpr SkRect kRect {0, 0, 100, 100};
+    constexpr SkPoint kPts[] {{kRect.fLeft, kRect.fTop}, {kRect.fRight, kRect.fBottom}};
+    constexpr SkColor kColors[] {SK_ColorRED, SK_ColorBLUE};
     SkPaint paint;
     sk_sp<SkShader> shader = SkGradientShader::MakeLinear(kPts, kColors, nullptr, 2,
                                                           SkShader::kClamp_TileMode);
@@ -25,12 +25,12 @@ DEF_SIMPLE_GM(stroke_rect_shader, canvas, 690, 300) {
     // Do a large initial translate so that local coords disagree with device coords significantly
     // for the first rect drawn.
     canvas->translate(kRect.centerX(), kRect.centerY());
-    static constexpr SkScalar kPad = 20;
+    constexpr SkScalar kPad = 20;
     for (auto aa : {false, true}) {
         paint.setAntiAlias(aa);
         canvas->save();
 
-        static constexpr SkScalar kStrokeWidth = 10;
+        constexpr SkScalar kStrokeWidth = 10;
         paint.setStrokeWidth(kStrokeWidth);
 
         paint.setStrokeJoin(SkPaint::kBevel_Join);