Move all static constants in dtoa/cached-powers.* to .rodata section

Source/wtf/dtoa/cached-powers.h

Index: Source/wtf/dtoa/cached-powers.h
diff --git a/Source/wtf/dtoa/cached-powers.h b/Source/wtf/dtoa/cached-powers.h
index fd01d73050d766ba8b284b9e5758bb5ba9e9bdf1..987cb3d5d0389511021628fb743419360eeb057b 100644
--- a/Source/wtf/dtoa/cached-powers.h
+++ b/Source/wtf/dtoa/cached-powers.h
@@ -39,10 +39,10 @@ namespace double_conversion {
 
         // Not all powers of ten are cached. The decimal exponent of two neighboring
         // cached numbers will differ by kDecimalExponentDistance.
-        static int kDecimalExponentDistance;
+        static const int kDecimalExponentDistance;
 
-        static int kMinDecimalExponent;
-        static int kMaxDecimalExponent;
+        static const int kMinDecimalExponent;
+        static const int kMaxDecimalExponent;
 
         // Returns a cached power-of-ten with a binary exponent in the range
         // [min_exponent; max_exponent] (boundaries included).
@@ -60,11 +60,6 @@ namespace double_conversion {
                                                      DiyFp* power,
                                                      int* found_exponent);
     };
-
-    // Initializes the table of cached powers used by the dtoa algorithm.
-    // This needs to be called when JSC is being initialized.
-    void initialize();
-
 }  // namespace double_conversion
 
 } // namespace WTF