Show a warning bubble when the IME extension is activated.

chrome/test/base/test_browser_window.h

Index: chrome/test/base/test_browser_window.h
diff --git a/chrome/test/base/test_browser_window.h b/chrome/test/base/test_browser_window.h
index 1526b2226b9e7ca5689fe4370e16b02830f29fac..6759ab75f356b1db0b9f73722766298ce43f5d39 100644
--- a/chrome/test/base/test_browser_window.h
+++ b/chrome/test/base/test_browser_window.h
@@ -140,6 +140,10 @@ class TestBrowserWindow : public BrowserWindow {
   void ExecuteExtensionCommand(const extensions::Extension* extension,
                                const extensions::Command& command) override;
   ExclusiveAccessContext* GetExclusiveAccessContext() override;
+  void ShowImeWarningBubble(
+      const extensions::Extension* extension,
+      const base::Callback<void(ImeWarningBubblePermissionStatus status)>&
+          callback) override {}
 
  protected:
   void DestroyBrowser() override {}