Don't show post extension install bubbles when incognito mode is forced.

chrome/browser/prefs/incognito_mode_prefs.h

Index: chrome/browser/prefs/incognito_mode_prefs.h
diff --git a/chrome/browser/prefs/incognito_mode_prefs.h b/chrome/browser/prefs/incognito_mode_prefs.h
index 791e8655ce02a914477da5db2a831b112a1fce1e..3215311b8c7c8d3fe08bd665aad7243c87d11f52 100644
--- a/chrome/browser/prefs/incognito_mode_prefs.h
+++ b/chrome/browser/prefs/incognito_mode_prefs.h
@@ -9,6 +9,7 @@
 
 class CommandLine;
 class PrefService;
+class Profile;
 
 namespace user_prefs {
 class PrefRegistrySyncable;
@@ -54,6 +55,11 @@ class IncognitoModePrefs {
   static bool ShouldLaunchIncognito(const CommandLine& command_line,
                                     const PrefService* prefs);
 
+  // Returns true if |profile| can open a new Browser. This checks the incognito
+  // availability policies and verifies if the |profile| type is allowed to
+  // open new windows.
+  static bool CanOpenBrowser(Profile* profile);
+
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(IncognitoModePrefs);
 };