Fix release builds for iOS. Add stub chromium impl for preferences.

BUG=711612

Review-Url: https://codereview.chromium.org/2818153002
Cr-Commit-Position: refs/heads/master@{#464763}
(cherry picked from commit 3b1c2e7)

Review-Url: https://codereview.chromium.org/2827173002 .
Cr-Commit-Position: refs/branch-heads/3071@{#72}
Cr-Branched-From: a106f0a-refs/heads/master@{#464641}

remoting/client/ios/BUILD.gn

@@ -39,6 +39,11 @@ source_set("ios_core") {
 
   if (!is_chrome_branded) {
     sources += [ "host_preferences_persistence_chromium.mm" ]
+  } else {
+    # TODO(nicholss): Until we have a private implementation of this, stub it
+    # with the chromium version. We still want the logic of is_chrome_branded
+    # but to get the release builds building we will just reuse the file.
+    sources += [ "host_preferences_persistence_chromium.mm" ]
   }
 
   public_deps = [