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

gm/bitmaprect.cpp

Index: gm/bitmaprect.cpp
diff --git a/gm/bitmaprect.cpp b/gm/bitmaprect.cpp
index 4db6e2fe95494650a9b403d088b1468f20cd9ff7..2a813004dff5205a74ec1e0444e6428724046b55 100644
--- a/gm/bitmaprect.cpp
+++ b/gm/bitmaprect.cpp
@@ -153,9 +153,9 @@ private:
 //////////////////////////////////////////////////////////////////////////////
 static void make_big_bitmap(SkBitmap* bitmap) {
 
-    static const int gXSize = 4096;
-    static const int gYSize = 4096;
-    static const int gBorderWidth = 10;
+    constexpr int gXSize = 4096;
+    constexpr int gYSize = 4096;
+    constexpr int gBorderWidth = 10;
 
     bitmap->allocN32Pixels(gXSize, gYSize);
     for (int y = 0; y < gYSize; ++y) {