Use base namespace for string16 in components and cloud_print.

cloud_print/common/win/cloud_print_utils.cc

Index: cloud_print/common/win/cloud_print_utils.cc
diff --git a/cloud_print/common/win/cloud_print_utils.cc b/cloud_print/common/win/cloud_print_utils.cc
index 71c9b53e7859a80da5a97fbfa6b128fb4b0eb740..ee3096410f636f11218c2c2af11f6f1e80d7b616 100644
--- a/cloud_print/common/win/cloud_print_utils.cc
+++ b/cloud_print/common/win/cloud_print_utils.cc
@@ -23,7 +23,7 @@ HRESULT GetLastHResult() {
   return error_code ? HRESULT_FROM_WIN32(error_code) : E_FAIL;
 }
 
-string16 LoadLocalString(DWORD id) {
+base::string16 LoadLocalString(DWORD id) {
   static wchar_t dummy = L'\0';
   HMODULE module = NULL;
   ::GetModuleHandleEx(GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT |
@@ -33,21 +33,21 @@ string16 LoadLocalString(DWORD id) {
   // LPCWSTR* and assign pointer to read-only memory with resource.
   int count = ::LoadString(module, id, reinterpret_cast<LPWSTR>(&buffer), 0);
   if (!buffer)
-    return string16();
-  return string16(buffer, buffer + count);
+    return base::string16();
+  return base::string16(buffer, buffer + count);
 }
 
-string16 GetErrorMessage(HRESULT hr) {
+base::string16 GetErrorMessage(HRESULT hr) {
   LPWSTR buffer = NULL;
   ::FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS |
                   FORMAT_MESSAGE_ALLOCATE_BUFFER,
                   0, hr, 0, reinterpret_cast<LPWSTR>(&buffer), 0, NULL);
-  string16 result(buffer);
+  base::string16 result(buffer);
   ::LocalFree(buffer);
   return result;
 }
 
-void SetGoogleUpdateUsage(const string16& product_id) {
+void SetGoogleUpdateUsage(const base::string16& product_id) {
   // Set appropriate key to 1 to let Omaha record usage.
   base::win::RegKey key;
   if (key.Create(HKEY_CURRENT_USER,