Reland of Add a NavigationThrottle to the public content/ interface

content/public/browser/navigation_handle.h

Index: content/public/browser/navigation_handle.h
diff --git a/content/public/browser/navigation_handle.h b/content/public/browser/navigation_handle.h
index c60babaa9939a4f0861eb1c0f2b7d9d7597c755f..033aca2962c6eb6c7818a7f53f4c1058a66c1be0 100644
--- a/content/public/browser/navigation_handle.h
+++ b/content/public/browser/navigation_handle.h
@@ -6,27 +6,70 @@
 #define CONTENT_PUBLIC_BROWSER_NAVIGATION_HANDLE_H_
 
 #include "content/common/content_export.h"
+#include "content/public/browser/navigation_throttle.h"
+#include "content/public/common/referrer.h"
 #include "net/base/net_errors.h"
+#include "ui/base/page_transition_types.h"
 
 class GURL;
 
 namespace content {
+class NavigationThrottle;
+class WebContents;
 
 // A NavigationHandle tracks information related to a single navigation.
 class CONTENT_EXPORT NavigationHandle {
  public:
   virtual ~NavigationHandle() {}
 
+  // Parameters available at navigation start time -----------------------------
+  //
+  // These parameters are always available during the navigation. Note that
+  // some may change during navigation (e.g. due to server redirects).
+
   // The URL the frame is navigating to. This may change during the navigation
   // when encountering a server redirect.
-  virtual const GURL& GetURL() const = 0;
+  virtual const GURL& GetURL() = 0;
+
+  // Whether the navigation is taking place in the main frame or in a subframe.
+  // This remains constant over the navigation lifetime.
+  virtual bool IsInMainFrame() = 0;
+
+  // The WebContents the navigation is taking place in.
+  WebContents* GetWebContents();
+
+  // Parameters available at network request start time ------------------------
+  //
+  // The following parameters are only available when the network request is
+  // made for the navigation (or at commit time if no network request is made).
+  // This corresponds to NavigationThrottle::WillSendRequest. They should not
+  // be queried before that.
+
+  // Whether the navigation is a POST or a GET. This may change during the
+  // navigation when encountering a server redirect.
+  virtual bool IsPost() = 0;
+
+  // Returns a sanitized version of the referrer for this request.
+  virtual const Referrer& GetReferrer() = 0;
+
+  // Whether the navigation was initiated by a user gesture. Note that this
+  // will return false for browser-initiated navigations.
+  // TODO(clamy): when PlzNavigate launches, this should return true for
+  // browser-initiated navigations.
+  virtual bool HasUserGesture() = 0;
+
+  // Returns the page transition type.
+  virtual ui::PageTransition GetPageTransition() = 0;
+
+  // Whether the target URL cannot be handled by the browser's internal protocol
+  // handlers.
+  virtual bool IsExternalProtocol() = 0;
+
+  // Navigation control flow --------------------------------------------------
 
   // The net error code if an error happened prior to commit. Otherwise it will
   // be net::OK.
-  virtual net::Error GetNetErrorCode() const = 0;
-
-  // Whether the navigation is taking place in the main frame or in a subframe.
-  virtual bool IsInMainFrame() const = 0;
+  virtual net::Error GetNetErrorCode() = 0;
 
   // Whether the navigation happened in the same page. This is only known
   // after the navigation has committed. It is an error to call this method
@@ -34,10 +77,44 @@
   virtual bool IsSamePage() = 0;
 
   // Whether the navigation has successfully committed a document.
-  virtual bool HasCommittedDocument() const = 0;
+  virtual bool HasCommittedDocument() = 0;
 
   // Whether an error page has committed for the navigation.
-  virtual bool HasCommittedErrorPage() const = 0;
+  virtual bool HasCommittedErrorPage() = 0;
+
+  // Testing methods ----------------------------------------------------------
+  //
+  // The following methods should be used exclusively for writing unit tests.
+
+  static scoped_ptr<NavigationHandle> CreateNavigationHandleForTesting(
+      const GURL& url,
+      bool is_main_frame,
+      WebContents* web_contents);
+
+  // Registers a NavigationThrottle for tests. The throttle can
+  // modify the request, pause the request or cancel the request. This will
+  // take ownership of the NavigationThrottle.
+  // Note: in non-test cases, NavigationThrottles should not be added directly
+  // but returned by the implementation of
+  // ContentBrowserClient::CreateThrottlesForNavigation. This ensures proper
+  // ordering of the throttles.
+  virtual void RegisterThrottleForTesting(
+      scoped_ptr<NavigationThrottle> navigation_throttle) = 0;
+
+  // Simulates the network request starting.
+  virtual NavigationThrottle::ThrottleCheckResult
+  CallWillStartRequestForTesting(bool is_post,
+                                 const Referrer& sanitized_referrer,
+                                 bool has_user_gesture,
+                                 ui::PageTransition transition,
+                                 bool is_external_protocol) = 0;
+
+  // Simulates the network request being redirected.
+  virtual NavigationThrottle::ThrottleCheckResult
+  CallWillRedirectRequestForTesting(const GURL& new_url,
+                                    bool new_method_is_post,
+                                    const GURL& new_referrer_url,
+                                    bool new_is_external_protocol) = 0;
 };
 
 }  // namespace content