Public side of English fallback CL

Change-Id: Ic6254af767545e783605a6f0cbe853601fcec236
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2405750Reviewed-by: Tommy Steimel <steimel@chromium.org>
Commit-Queue: Becca Hughes <beccahughes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#806265}

chrome/browser/media/kaleidoscope/kaleidoscope_ui.cc

@@ -32,6 +32,7 @@ namespace {
 // Wraps the strings in JS so they can be accessed by the code. The strings are
 // placed on the window object so they can always be accessed.
 const char kStringWrapper[] =
+    "window.KALEIDOSCOPE_STRINGS_FALLBACK = new Map(Object.entries(%s));"
     "window.KALEIDOSCOPE_STRINGS = new Map(Object.entries(%s));";
 
 bool OnShouldHandleRequest(const std::string& path) {
@@ -182,22 +183,26 @@ int GetResourceForLocale(const std::string& locale) {
 
 #endif  // BUILDFLAG(ENABLE_KALEIDOSCOPE)
 
-void OnStringsRequest(const std::string& path,
-                      content::WebUIDataSource::GotDataCallback callback) {
-  DCHECK(OnShouldHandleRequest(path));
-
+std::string GetStringsForLocale(const std::string& locale) {
   std::string str;
 #if BUILDFLAG(ENABLE_KALEIDOSCOPE)
-  auto locale = base::ToLowerASCII(base::i18n::GetConfiguredLocale());
-
   str = ui::ResourceBundle::GetSharedInstance().LoadDataResourceString(
       GetResourceForLocale(locale));
-#else
+#endif
+  return str;
+}
 
-#endif  // BUILDFLAG(ENABLE_KALEIDOSCOPE)
+void OnStringsRequest(const std::string& path,
+                      content::WebUIDataSource::GotDataCallback callback) {
+  DCHECK(OnShouldHandleRequest(path));
+
+  auto str_lang = GetStringsForLocale(
+      base::ToLowerASCII(base::i18n::GetConfiguredLocale()));
+  auto str_lang_en = GetStringsForLocale("en");
 
   base::RefCountedString* ref_contents = new base::RefCountedString();
-  ref_contents->data() = base::StringPrintf(kStringWrapper, str.c_str());
+  ref_contents->data() =
+      base::StringPrintf(kStringWrapper, str_lang_en.c_str(), str_lang.c_str());
   std::move(callback).Run(ref_contents);
 }