Add 'NavigationHandle::QueueConsoleMessage'.

content/browser/frame_host/navigation_handle_impl.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_FRAME_HOST_NAVIGATION_HANDLE_IMPL_H_
 #define CONTENT_BROWSER_FRAME_HOST_NAVIGATION_HANDLE_IMPL_H_
 
 #include "content/public/browser/navigation_handle.h"
 
 #include <stddef.h>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_vector.h"
 #include "content/browser/frame_host/frame_tree_node.h"
 #include "content/browser/frame_host/render_frame_host_impl.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/navigation_data.h"
 #include "content/public/browser/navigation_throttle.h"
+#include "content/public/common/console_message_level.h"
 #include "url/gurl.h"
 
 struct FrameHostMsg_DidCommitProvisionalLoad_Params;
 
 namespace content {
 
 class NavigatorDelegate;
 class ResourceRequestBodyImpl;
 class ServiceWorkerContextWrapper;
 class ServiceWorkerNavigationHandle;
@@ skipping 195 matching lines @@
       bool same_page,
       RenderFrameHostImpl* render_frame_host);
 
   // Called during commit. Takes ownership of the embedder's NavigationData
   // instance. This NavigationData may have been cloned prior to being added
   // here.
   void set_navigation_data(std::unique_ptr<NavigationData> navigation_data) {
     navigation_data_ = std::move(navigation_data);
   }
 
+  // Adds a console message to the NavigationHandle's message queue. Messages
+  // queued before the navigation is ready to commit will be delivered to the
+  // final RenderFrameHost upon commit. Messages queued after the navigation has
+  // committed will be delivered immediately.

[clamy, 2016/06/29 11:07:28]

The navigation commit corresponds to the destruction of this NavigationHandle,
so this comment seems a bit misleading to me. How about "at commit time" instead
of "after the navigation has committed".

There's also the question of what happens if the navigation doesn't commit.
Should we just drop them? Deliver them to the current RenderFrameHost of the
FrameTreeNode (maybe only if it was renderer initiated)? Once we come to an
agreement, this should be precised in the comment.

+  void QueueConsoleMessage(ConsoleMessageLevel level,

[nasko, 2016/06/28 22:25:46]

bikeshed: AppendConsoleMessage? Queue to me implies that it always adds to a
queue, which seems incorrect based on the description. Appending is always what
we want to do, regardless of whether we need to keep them in a queue for some
period of time.

+                           const std::string& message);
+
  private:
   friend class NavigationHandleImplTest;
 
   // Used to track the state the navigation is currently in.
   enum State {
     INITIAL = 0,
     WILL_SEND_REQUEST,
     DEFERRING_START,
     WILL_REDIRECT_REQUEST,
     DEFERRING_REDIRECT,
@@ skipping 14 matching lines @@
                        int pending_nav_entry_id);
 
   NavigationThrottle::ThrottleCheckResult CheckWillStartRequest();
   NavigationThrottle::ThrottleCheckResult CheckWillRedirectRequest();
   NavigationThrottle::ThrottleCheckResult CheckWillProcessResponse();
 
   // Helper function to run and reset the |complete_callback_|. This marks the
   // end of a round of NavigationThrottleChecks.
   void RunCompleteCallback(NavigationThrottle::ThrottleCheckResult result);
 
+  // Outputs the messages in |console_queue_| to the relevant RenderFrameHost,
+  // in FIFO order. This method must be called after a response has been
+  // delivered for processing, and will clear out |console_queue_| as a side
+  // effect of sending the messages.
+  virtual void DumpMessagesToConsole();

[clamy, 2016/06/29 11:07:28]

Why virtual?

+
   // Used in tests.
   State state() const { return state_; }
 
   // See NavigationHandle for a description of those member variables.
   GURL url_;
   Referrer sanitized_referrer_;
   bool has_user_gesture_;
   ui::PageTransition transition_;
   bool is_external_protocol_;
   net::Error net_error_code_;
@@ skipping 39 matching lines @@
   ThrottleChecksFinishedCallback complete_callback_;
 
   // PlzNavigate
   // Manages the lifetime of a pre-created ServiceWorkerProviderHost until a
   // corresponding ServiceWorkerNetworkProvider is created in the renderer.
   std::unique_ptr<ServiceWorkerNavigationHandle> service_worker_handle_;
 
   // Embedder data tied to this navigation.
   std::unique_ptr<NavigationData> navigation_data_;
 
+  // A queue of messages to be delivered to the devtools console upon commit.
+  std::queue<std::pair<ConsoleMessageLevel, const std::string>> console_queue_;
+
   DISALLOW_COPY_AND_ASSIGN(NavigationHandleImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_NAVIGATION_HANDLE_IMPL_H_