Update some uses of char16 to use the base:: namespace.

sandbox/win/src/sandbox_policy_base.cc

Index: sandbox/win/src/sandbox_policy_base.cc
diff --git a/sandbox/win/src/sandbox_policy_base.cc b/sandbox/win/src/sandbox_policy_base.cc
index 42006e65d2777b8ee2f061624740b9e60e1311d0..758a8bea58c59a226a0463f724bcc32e770422fb 100644
--- a/sandbox/win/src/sandbox_policy_base.cc
+++ b/sandbox/win/src/sandbox_policy_base.cc
@@ -414,8 +414,8 @@ ResultCode PolicyBase::AddDllToUnload(const wchar_t* dll_name) {
   return SBOX_ALL_OK;
 }
 
-ResultCode PolicyBase::AddKernelObjectToClose(const char16* handle_type,
-                                              const char16* handle_name) {
+ResultCode PolicyBase::AddKernelObjectToClose(const base::char16* handle_type,
+                                              const base::char16* handle_name) {
   return handle_closer_.AddHandle(handle_type, handle_name);
 }