Fix a bug where installing an extension in incognito would not show the help

chrome/browser/extensions/extension_install_ui.cc

Index: chrome/browser/extensions/extension_install_ui.cc
diff --git a/chrome/browser/extensions/extension_install_ui.cc b/chrome/browser/extensions/extension_install_ui.cc
index 2f1efd5039644cac91196e62f75da7d02cef0f25..71c74088dfdfbe837f45ffc7a1a815e9af9d1098 100644
--- a/chrome/browser/extensions/extension_install_ui.cc
+++ b/chrome/browser/extensions/extension_install_ui.cc
@@ -128,10 +128,15 @@ void ExtensionInstallUI::OnInstallSuccess(const Extension* extension) {
     return;
   }
 
-  // GetLastActiveWithProfile will fail on the build bots. This needs to be
-  // implemented differently if any test is created which depends on
-  // ExtensionInstalledBubble showing.
-  Browser* browser = BrowserList::GetLastActiveWithProfile(profile_);
+  // Note that browser actions don't appear in incognito mode initially,
+  // so be sure to use a normal browser window.
+  Profile* profile = profile_;
+  if (extension->browser_action())
+    profile = profile->GetOriginalProfile();
+  Browser* browser = Browser::GetOrCreateTabbedBrowser(profile);
+  if (browser->tab_count() == 0)
+    browser->AddBlankTab(true);
+  browser->window()->Show();
 
   if (extension->GetFullLaunchURL().is_valid()) {
     std::string hash_params = "app-id=";