Move JoinString to the base namespace.

base/strings/string_util.h

Index: base/strings/string_util.h
diff --git a/base/strings/string_util.h b/base/strings/string_util.h
index e4abce2147eb84c1668e1edb7f23f1986a2bfe35..b75a9f88b848a5ce2cad42dbabe70cc8b35ee9fe 100644
--- a/base/strings/string_util.h
+++ b/base/strings/string_util.h
@@ -491,6 +491,12 @@ BASE_EXPORT char16* WriteInto(base::string16* str, size_t length_with_null);
 BASE_EXPORT wchar_t* WriteInto(std::wstring* str, size_t length_with_null);
 #endif
 
+// Does the opposite of SplitString().
+BASE_EXPORT std::string JoinString(const std::vector<std::string>& parts,
+                                   StringPiece separator);
+BASE_EXPORT string16 JoinString(const std::vector<string16>& parts,
+                                StringPiece16 separator);
+
 }  // namespace base
 
 #if defined(OS_WIN)
@@ -501,22 +507,6 @@ BASE_EXPORT wchar_t* WriteInto(std::wstring* str, size_t length_with_null);
 #error Define string operations appropriately for your platform
 #endif
 
-//-----------------------------------------------------------------------------
-
-// Does the opposite of SplitString().
-BASE_EXPORT base::string16 JoinString(const std::vector<base::string16>& parts,
-                                      base::char16 s);
-BASE_EXPORT std::string JoinString(
-    const std::vector<std::string>& parts, char s);
-
-// Join |parts| using |separator|.
-BASE_EXPORT std::string JoinString(
-    const std::vector<std::string>& parts,
-    const std::string& separator);
-BASE_EXPORT base::string16 JoinString(
-    const std::vector<base::string16>& parts,
-    const base::string16& separator);
-
 // Replace $1-$2-$3..$9 in the format string with |a|-|b|-|c|..|i| respectively.
 // Additionally, any number of consecutive '$' characters is replaced by that
 // number less one. Eg $$->$, $$$->$$, etc. The offsets parameter here can be