Remove enable_notifications build flag and define

This flag is not overridable and is set everywhere except iOS. All users except
one are in //chrome which isn't compiled on iOS. So in all of these cases we
can remove the conditionals and always compile the code.

For the one case in ui, The conditional is replaced with !is_ios. This was also
done with the .grd file in chrome. This file has a lot of iOS conditionals and
I want to be sure it's not needed on iOS before inlining them unconditionally.
Then we can delete all of the iOS conditionals.

BUG=671706

Review-Url: https://codereview.chromium.org/2555833002
Cr-Commit-Position: refs/heads/master@{#436813}
diff --git a/chrome/browser/browser_process_impl.cc b/chrome/browser/browser_process_impl.cc
index 5be550d8..a149631 100644
--- a/chrome/browser/browser_process_impl.cc
+++ b/chrome/browser/browser_process_impl.cc
@@ -1139,7 +1139,7 @@
 }
 
 void BrowserProcessImpl::CreateNotificationPlatformBridge() {
-#if (defined(OS_ANDROID) || defined(OS_MACOSX)) && defined(ENABLE_NOTIFICATIONS)
+#if (defined(OS_ANDROID) || defined(OS_MACOSX))
   DCHECK(!notification_bridge_);
   notification_bridge_.reset(NotificationPlatformBridge::Create());
   created_notification_bridge_ = true;
@@ -1149,7 +1149,7 @@
 void BrowserProcessImpl::CreateNotificationUIManager() {
 // Android does not use the NotificationUIManager anymore
 // All notification traffic is routed through NotificationPlatformBridge.
-#if defined(ENABLE_NOTIFICATIONS) && !defined(OS_ANDROID)
+#if !defined(OS_ANDROID)
   DCHECK(!notification_ui_manager_);
   notification_ui_manager_.reset(NotificationUIManager::Create());
   created_notification_ui_manager_ = true;