Add base:: to string16s in chrome/.

chrome/installer/util/installer_util_test_common.cc

Index: chrome/installer/util/installer_util_test_common.cc
diff --git a/chrome/installer/util/installer_util_test_common.cc b/chrome/installer/util/installer_util_test_common.cc
index bc46385214cb4b445d45d5e2496b5a8bd42b7b12..6c1553732ae841c5c366b1d50a569d27663fb42e 100644
--- a/chrome/installer/util/installer_util_test_common.cc
+++ b/chrome/installer/util/installer_util_test_common.cc
@@ -17,9 +17,9 @@ namespace test {
 bool CopyFileHierarchy(const base::FilePath& from, const base::FilePath& to) {
   // In SHFILEOPSTRUCT below, |pFrom| and |pTo| have to be double-null
   // terminated: http://msdn.microsoft.com/library/bb759795.aspx
-  string16 double_null_from(from.value());
+  base::string16 double_null_from(from.value());
   double_null_from.push_back(L'\0');
-  string16 double_null_to(to.value());
+  base::string16 double_null_to(to.value());
   double_null_to.push_back(L'\0');
 
   SHFILEOPSTRUCT file_op = {};