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 f45cd7b3c7bcdbad417e54ea39fda8c42d3c056f..8de442a8b3281b2d3f5e406bd3460acb58b64636 100644
--- a/content/public/browser/content_browser_client.h
+++ b/content/public/browser/content_browser_client.h
@@ -98,6 +98,8 @@ class LocationProvider;
 class MediaObserver;
 class NavigatorConnectContext;
 class NavigatorConnectServiceFactory;
+class NavigationHandle;
+class NavigationThrottle;
 class PlatformNotificationService;
 class PresentationServiceDelegate;
 class QuotaPermissionContext;
@@ -652,6 +654,16 @@ class CONTENT_EXPORT ContentBrowserClient {
   // 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 NavigationThrottle for a

[nasko, 2015/09/04 23:36:49]

nit: one or more implies the next word being plural.

[clamy, 2015/09/08 16:27:19]

Done.

+  // navigation. 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 registered.

[nasko, 2015/09/04 23:36:49]

nit: s/registered/provided/, since the embedder on longer registers them
directly.

[clamy, 2015/09/08 16:27:19]

Done.

+  // Note that the ownership of the NavigationThrottles returned will be taken
+  // by the NavigationHandle.

[nasko, 2015/09/04 23:36:49]

This note won't be necessary if we have ScopedVector, which will clearly
indicate ownership semantics.

[clamy, 2015/09/08 16:27:19]

Done.

+  virtual std::vector<NavigationThrottle*> AddNavigationThrottles(
+      NavigationHandle* navigation_handle,
+      WebContents* web_contents);
+
   // Populates |mappings| with all files that need to be mapped before launching
   // a child process.
 #if defined(OS_ANDROID)