Add 'NavigationHandle::QueueConsoleMessage'.

content/browser/frame_host/navigation_handle_impl.cc

Index: content/browser/frame_host/navigation_handle_impl.cc
diff --git a/content/browser/frame_host/navigation_handle_impl.cc b/content/browser/frame_host/navigation_handle_impl.cc
index a31508c18e0e1ec27973f27cbb510d2398d4090a..a445944a51e56aa77f306880b380d44e221b24e0 100644
--- a/content/browser/frame_host/navigation_handle_impl.cc
+++ b/content/browser/frame_host/navigation_handle_impl.cc
@@ -244,6 +244,14 @@ void NavigationHandleImpl::CancelDeferredNavigation(
   RunCompleteCallback(result);
 }
 
+void NavigationHandleImpl::QueueConsoleMessage(ConsoleMessageLevel level,
+                                               const std::string& message) {
+  console_queue_.emplace(level, message);
+
+  if (state_ >= WILL_PROCESS_RESPONSE)
+    DumpMessagesToConsole();
+}
+
 void NavigationHandleImpl::RegisterThrottleForTesting(
     std::unique_ptr<NavigationThrottle> navigation_throttle) {
   throttles_.push_back(std::move(navigation_throttle));
@@ -390,6 +398,13 @@ void NavigationHandleImpl::WillProcessResponse(
   state_ = WILL_PROCESS_RESPONSE;
   complete_callback_ = callback;
 
+  // Clear out the pending console message queue now that we have a
+  // render_frame_host.
+  //
+  // TODO(mkwst): Move this to 'ReadyToCommitNavigation' as part of the work
+  // in https://crbug.com/621856.
+  DumpMessagesToConsole();

[clamy, 2016/06/28 11:30:38]

This is problematic right now for transfer navigations. I'm not thrilled about
landing this until we get ReadyToCommitNavigation to execute on all sorts of
navigations.

[Mike West, 2016/06/28 12:22:33]

It's no more problematic than getting the RenderFrameHost in the first place, is
it?

We could move it to 'ReadyToCommitNavigation' now, and just recognize that we'll
lose some console messages in the meantime. Though, now that I think about it,
that seems incorrect for cases in which the throttle will actually cancel the
navigation. In those cases, we'll never actually hit ReadyToCommitNavigation
(see line 412 below)... Hrm.

+
   // Notify each throttle of the response.
   NavigationThrottle::ThrottleCheckResult result = CheckWillProcessResponse();
 
@@ -541,4 +556,15 @@ void NavigationHandleImpl::RunCompleteCallback(
   // destruction.
 }
 
+void NavigationHandleImpl::DumpMessagesToConsole() {
+  DCHECK_GE(state_, WILL_PROCESS_RESPONSE);
+  DCHECK(GetRenderFrameHost());
+
+  while (!console_queue_.empty()) {
+    GetRenderFrameHost()->AddMessageToConsole(console_queue_.front().first,
+                                              console_queue_.front().second);
+    console_queue_.pop();
+  }
+}
+
 }  // namespace content