libaddressinput: Add fallback data for US address validation.

third_party/libaddressinput/chromium/cpp/src/retriever.cc

Index: third_party/libaddressinput/chromium/cpp/src/retriever.cc
diff --git a/third_party/libaddressinput/chromium/cpp/src/retriever.cc b/third_party/libaddressinput/chromium/cpp/src/retriever.cc
index 7dd788107efec20b5b6541b144972e9810af6689..b7c17a55e0374eebdf5c01bc29e36f4d9b98780e 100644
--- a/third_party/libaddressinput/chromium/cpp/src/retriever.cc
+++ b/third_party/libaddressinput/chromium/cpp/src/retriever.cc
@@ -26,6 +26,7 @@
 #include <string>
 #include <utility>
 
+#include "fallback_data_store.h"
 #include "lookup_key_util.h"
 #include "util/stl_util.h"
 
@@ -79,14 +80,19 @@ void Retriever::OnDataRetrievedFromStorage(bool success,
 
 void Retriever::OnDownloaded(bool success,
                              const std::string& url,
-                             const std::string& data) {
+                             const std::string& downloaded_data) {
+  std::string response;
   const std::string& key = lookup_key_util_.GetKeyForUrl(url);
   if (success) {
-    storage_->Put(key, data);
+    storage_->Put(key, downloaded_data);
+    response = downloaded_data;
+  } else {
+    success = FallbackDataStore::Get(key, &response);
   }
+
   scoped_ptr<Callback> retrieved = GetCallbackForKey(key);
   if (retrieved != NULL) {
-    (*retrieved)(success, key, success ? data : std::string());
+    (*retrieved)(success, key, response);
   }
 }