Add a warning for the deprecation of content-initiated data URL navigations

content/browser/frame_host/navigation_handle_impl.cc

 // 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.
 
 #include "content/browser/frame_host/navigation_handle_impl.h"
 
 #include <iterator>
 
 #include "base/debug/dump_without_crashing.h"
 #include "base/logging.h"
@@ skipping 620 matching lines @@
   navigation_type_ = navigation_type;
 
   // If an error page reloads, net_error_code might be 200 but we still want to
   // count it as an error page.
   if (params.base_url.spec() == kUnreachableWebDataURL ||
       net_error_code_ != net::OK) {
     state_ = DID_COMMIT_ERROR_PAGE;
   } else {
     state_ = DID_COMMIT;
   }
+
+  if (url_.SchemeIs(url::kDataScheme) && IsInMainFrame() &&
+      IsRendererInitiated()) {
+    GetRenderFrameHost()->AddMessageToConsole(
+        CONSOLE_MESSAGE_LEVEL_WARNING,
+        "Upcoming versions will block content-initiated top frame navigations "
+        "to data: URLs. For more information, see https://goo.gl/BaZAea.");
+  }
 }
 
 void NavigationHandleImpl::Transfer() {
   DCHECK(!IsBrowserSideNavigationEnabled());
   // This is an actual transfer. Inform the NavigationResourceThrottle. This
   // will allow to mark the URLRequest as transferring. When it is marked as
   // transferring, the URLRequest can no longer be cancelled by its original
   // RenderFrame. Instead it will persist until being picked up by the transfer
   // RenderFrame, even if the original RenderFrame is destroyed.
   BrowserThread::PostTask(BrowserThread::IO, FROM_HERE, transfer_callback_);
@@ skipping 232 matching lines @@
       content::AncestorThrottle::MaybeCreateThrottleFor(this);
   if (ancestor_throttle)
     throttles_.push_back(std::move(ancestor_throttle));
 
   throttles_.insert(throttles_.begin(),
                     std::make_move_iterator(throttles_to_register.begin()),
                     std::make_move_iterator(throttles_to_register.end()));
 }
 
 }  // namespace content