Chrome Cleaner UI: Add an initial controller class.

For now, the controller class will return dummy strings to be
displayed in the new Chrome Cleaner dialog until we are ready to
provide real strings.

BUG=690020

Review-Url: https://codereview.chromium.org/2789693003
Cr-Commit-Position: refs/heads/master@{#461593}
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index dfa5ad9..9f6f8259 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -1758,6 +1758,8 @@
       "safe_browsing/settings_reset_prompt/settings_reset_prompt_model.h",
       "safe_browsing/settings_reset_prompt/settings_reset_prompt_prefs_manager.cc",
       "safe_browsing/settings_reset_prompt/settings_reset_prompt_prefs_manager.h",
+      "safe_browsing/srt_prompt_controller.cc",
+      "safe_browsing/srt_prompt_controller.h",
       "search/hotword_audio_history_handler.cc",
       "search/hotword_audio_history_handler.h",
       "search/hotword_client.h",