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

gm/pictureimagegenerator.cpp

Index: gm/pictureimagegenerator.cpp
diff --git a/gm/pictureimagegenerator.cpp b/gm/pictureimagegenerator.cpp
index 60e979fc3c063ef2982d0c739d97c04a385e5420..95efbb2055be298dddca0caebd746a5f18e10d56 100644
--- a/gm/pictureimagegenerator.cpp
+++ b/gm/pictureimagegenerator.cpp
@@ -16,10 +16,10 @@
 #include "SkPictureRecorder.h"
 
 static void draw_vector_logo(SkCanvas* canvas, const SkRect& viewBox) {
-    static const char kSkiaStr[] = "SKIA";
-    static const SkScalar kGradientPad = .1f;
-    static const SkScalar kVerticalSpacing = 0.25f;
-    static const SkScalar kAccentScale = 1.20f;
+    constexpr char kSkiaStr[] = "SKIA";
+    constexpr SkScalar kGradientPad = .1f;
+    constexpr SkScalar kVerticalSpacing = 0.25f;
+    constexpr SkScalar kAccentScale = 1.20f;
 
     SkPaint paint;
     paint.setAntiAlias(true);