Revert of Add a NavigationThrottle to the public content/ interface

content/public/browser/content_browser_client.h

Index: content/public/browser/content_browser_client.h
diff --git a/content/public/browser/content_browser_client.h b/content/public/browser/content_browser_client.h
index 55569fb01dbe9cac48e083d8314ce33afe4ec161..2c6734cf1f7c073f8180a46bb76201434db02647 100644
--- a/content/public/browser/content_browser_client.h
+++ b/content/public/browser/content_browser_client.h
@@ -16,7 +16,6 @@
 #include "base/memory/scoped_vector.h"
 #include "base/values.h"
 #include "content/public/browser/certificate_request_result_type.h"
-#include "content/public/browser/navigation_throttle.h"
 #include "content/public/common/content_client.h"
 #include "content/public/common/media_stream_request.h"
 #include "content/public/common/resource_type.h"
@@ -97,7 +96,6 @@
 class ExternalVideoSurfaceContainer;
 class LocationProvider;
 class MediaObserver;
-class NavigationHandle;
 class NavigatorConnectContext;
 class NavigatorConnectServiceFactory;
 class PlatformNotificationService;
@@ -671,14 +669,6 @@
   // Allows the embedder to record |metric| for a specific |url|.
   virtual void RecordURLMetric(const std::string& metric, const GURL& url) {}
 
-  // Allows the embedder to register one or more NavigationThrottles for the
-  // navigation indicated by |navigation_handle|.  A NavigationThrottle is used
-  // to control the flow of a navigation on the UI thread. The embedder is
-  // guaranteed that the throttles will be executed in the order they were
-  // provided.
-  virtual ScopedVector<NavigationThrottle> CreateThrottlesForNavigation(
-      NavigationHandle* navigation_handle);
-
   // Populates |mappings| with all files that need to be mapped before launching
   // a child process.
 #if defined(OS_ANDROID)