Log messages regarding why app banners aren't displayed to the console

chrome/renderer/chrome_render_frame_observer.cc

 // Copyright 2013 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 "chrome/renderer/chrome_render_frame_observer.h"
 
 #include <limits>
 #include <string>
 #include <vector>
 
@@ skipping 82 matching lines @@
   if (handled)
     return false;
 
   IPC_BEGIN_MESSAGE_MAP(ChromeRenderFrameObserver, message)
     IPC_MESSAGE_HANDLER(ChromeViewMsg_RequestThumbnailForContextNode,
                         OnRequestThumbnailForContextNode)
     IPC_MESSAGE_HANDLER(PrintMsg_PrintNodeUnderContextMenu,
                         OnPrintNodeUnderContextMenu)
     IPC_MESSAGE_HANDLER(ChromeViewMsg_AppBannerPromptRequest,
                         OnAppBannerPromptRequest)
+    IPC_MESSAGE_HANDLER(ChromeViewMsg_AppBannerDebugMessageRequest,
+                        OnAppBannerDebugMessageRequest)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
 
   return handled;
 }
 
 void ChromeRenderFrameObserver::OnSetIsPrerendering(bool is_prerendering) {
   if (is_prerendering) {
     // If the PrerenderHelper for this frame already exists, don't create it. It
     // can already be created for subframes during handling of
@@ skipping 88 matching lines @@
   // by blink and may not exist when the request is sent.
   blink::WebAppBannerPromptReply reply = blink::WebAppBannerPromptReply::None;
   blink::WebString web_platform(base::UTF8ToUTF16(platform));
   blink::WebVector<blink::WebString> web_platforms(&web_platform, 1);
   render_frame()->GetWebFrame()->willShowInstallBannerPrompt(
       request_id, web_platforms, &reply);
 
   Send(new ChromeViewHostMsg_AppBannerPromptReply(
       routing_id(), request_id, reply));
 }
+
+void ChromeRenderFrameObserver::OnAppBannerDebugMessageRequest(
+    const std::string& message) {
+  render_frame()->GetWebFrame()->addMessageToConsole(blink::WebConsoleMessage(
+      blink::WebConsoleMessage::LevelDebug, base::UTF8ToUTF16(message)));
+}