[iOS] Remove ChromeBrowserState::ExitType (dead code)

Review URL: https://codereview.chromium.org/1471743002

Cr-Commit-Position: refs/heads/master@{#361372}

ios/chrome/browser/application_context_impl.cc

@@ -88,12 +88,6 @@ void ApplicationContextImpl::OnAppEnterForeground() {
   variations::VariationsService* variations_service = GetVariationsService();
   if (variations_service)
     variations_service->OnAppEnterForeground();
-
-  std::vector<ios::ChromeBrowserState*> loaded_browser_state =
-      GetChromeBrowserStateManager()->GetLoadedBrowserStates();
-  for (ios::ChromeBrowserState* browser_state : loaded_browser_state) {
-    browser_state->SetExitType(ios::ChromeBrowserState::EXIT_CRASHED);
-  }
 }
 
 void ApplicationContextImpl::OnAppEnterBackground() {
@@ -108,7 +102,6 @@ void ApplicationContextImpl::OnAppEnterBackground() {
       history_service->HandleBackgrounding();
     }
 
-    browser_state->SetExitType(ios::ChromeBrowserState::EXIT_NORMAL);
     PrefService* browser_state_prefs = browser_state->GetPrefs();
     if (browser_state_prefs)
       browser_state_prefs->CommitPendingWrite();

ios/public/provider/chrome/browser/browser_state/chrome_browser_state.h

@@ -31,11 +31,6 @@ namespace ios {
 // This class is a Chrome-specific extension of the BrowserState interface.
 class ChromeBrowserState : public web::BrowserState {
  public:
-  enum ExitType {
-    EXIT_NORMAL,
-    EXIT_CRASHED,
-  };
-
   ~ChromeBrowserState() override {}
 
   // Returns the ChromeBrowserState corresponding to the given BrowserState.
@@ -75,18 +70,6 @@ class ChromeBrowserState : public web::BrowserState {
   // a syncable_prefs::PrefServiceSyncable.
   virtual syncable_prefs::PrefServiceSyncable* GetSyncablePrefs() = 0;
 
-  // Sets the ExitType for the ChromeBrowserState. This may be invoked multiple
-  // times during shutdown; only the first such change (the transition from
-  // EXIT_CRASHED to one of the other values) is written to prefs, any later
-  // calls are ignored.
-  //
-  // NOTE: this is invoked internally on a normal shutdown, but is public so
-  // that it can be invoked to handle backgrounding/foregrounding.
-  virtual void SetExitType(ExitType exit_type) = 0;
-
-  // Returns how the last session was shutdown.
-  virtual ExitType GetLastSessionExitType() = 0;
-
   // Deletes all network related data since |time|. It deletes transport
   // security state since |time| and it also deletes HttpServerProperties data.
   // Works asynchronously, however if the |completion| callback is non-null, it