Add 'NavigationHandle::QueueConsoleMessage'.

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 54924a4ec63d1e616ce8f3c83a5b1847b2d0b92a..53b9d4ffe31461d0d7e2232290669bea885fc31e 100644
--- a/content/public/browser/navigation_handle.h
+++ b/content/public/browser/navigation_handle.h
@@ -9,6 +9,7 @@
 
 #include "content/common/content_export.h"
 #include "content/public/browser/navigation_throttle.h"
+#include "content/public/common/console_message_level.h"
 #include "content/public/common/referrer.h"
 #include "net/base/net_errors.h"
 #include "ui/base/page_transition_types.h"
@@ -159,6 +160,13 @@ class CONTENT_EXPORT NavigationHandle {
   virtual void CancelDeferredNavigation(
       NavigationThrottle::ThrottleCheckResult result) = 0;
 
+  // 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.
+  virtual void QueueConsoleMessage(ConsoleMessageLevel level,

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

The policy of content is not to add a method to the public API if it is not used
outside of content. Since this is not happening in this patch, this should be
added to NavigationHandleImpl instead, and then made available to the public API
when there is an external use case.

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

You're right, sorry. I'd convinced myself that
https://codereview.chromium.org/2025683003 was calling this from //chrome
because that's where the BrowsingDataRemover lives. Fortunately, the throttle is
implemented in //content. I'll drop this addition. :)

+                                   const std::string& message) = 0;
+
   // Testing methods ----------------------------------------------------------
   //
   // The following methods should be used exclusively for writing unit tests.