Move StringToLowerASCII to base namespace

base/environment.cc

Index: base/environment.cc
diff --git a/base/environment.cc b/base/environment.cc
index 280469da205cd1acd8672c341cef84b03e4044c4..c5477305a1fa7ace523aadc9a46a5408e6559cd1 100644
--- a/base/environment.cc
+++ b/base/environment.cc
@@ -36,7 +36,7 @@ class EnvironmentImpl : public base::Environment {
     if (first_char >= 'a' && first_char <= 'z')
       alternate_case_var = StringToUpperASCII(std::string(variable_name));
     else if (first_char >= 'A' && first_char <= 'Z')
-      alternate_case_var = StringToLowerASCII(std::string(variable_name));
+      alternate_case_var = base::StringToLowerASCII(std::string(variable_name));
     else
       return false;
     return GetVarImpl(alternate_case_var.c_str(), result);