Remove CRWNetworkActivityIndicatorManager.

ios/web/net/request_tracker_impl.h

Index: ios/web/net/request_tracker_impl.h
diff --git a/ios/web/net/request_tracker_impl.h b/ios/web/net/request_tracker_impl.h
index 9e53f6118efbac96a075e36598b8f763d4d4a983..0376b3c8fc2a769b8c2d55412a0ddb1c1732f0ba 100644
--- a/ios/web/net/request_tracker_impl.h
+++ b/ios/web/net/request_tracker_impl.h
@@ -329,10 +329,6 @@ class RequestTrackerImpl
   // only from the IO thread.
   NSString* UnsafeDescription();
 
-  // Generates a string unique to this RequestTrackerImpl to use with the
-  // CRWNetworkActivityIndicatorManager.
-  NSString* GetNetworkActivityKey();
-
 #pragma mark Non thread-safe fields, only accessed from the main thread.
   // The RequestTrackerImpl delegate. All changes and access to this object
   // should be done on the main thread.