Implement sidebar support for extension action popups

chrome/test/base/testing_browser_process.h

Index: chrome/test/base/testing_browser_process.h
diff --git a/chrome/test/base/testing_browser_process.h b/chrome/test/base/testing_browser_process.h
index 090689730f38baa870942d041c94a738d6e85187..08822a8ee4f3d016679f1d260728977e9485b688 100644
--- a/chrome/test/base/testing_browser_process.h
+++ b/chrome/test/base/testing_browser_process.h
@@ -73,6 +73,7 @@ class TestingBrowserProcess : public BrowserProcess {
   BackgroundModeManager* background_mode_manager() override;
   void set_background_mode_manager_for_test(
       scoped_ptr<BackgroundModeManager> manager) override;
+  SidebarManager* sidebar_manager() override;
   StatusTray* status_tray() override;
   SafeBrowsingService* safe_browsing_service() override;
   safe_browsing::ClientSideDetectionService* safe_browsing_detection_service()