Added IsPublicSession utility function to profiles_state

chrome/browser/profiles/profiles_state.h

Index: chrome/browser/profiles/profiles_state.h
diff --git a/chrome/browser/profiles/profiles_state.h b/chrome/browser/profiles/profiles_state.h
index 758b649bdf2a6e47d95445ad360a6cca45e360ab..d97a6c8a02165c4f482ca6c09783c23d19964176 100644
--- a/chrome/browser/profiles/profiles_state.h
+++ b/chrome/browser/profiles/profiles_state.h
@@ -108,6 +108,9 @@ void SetLastUsedProfile(const std::string& profile_dir);
 // and they are all locked.
 bool AreAllNonChildNonSupervisedProfilesLocked();
 
+// Returns whether a public session is being run currently.
+bool IsPublicSession();
+
 }  // namespace profiles
 
 #endif  // CHROME_BROWSER_PROFILES_PROFILES_STATE_H_