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

chrome/browser/banners/app_banner_manager.cc

Index: chrome/browser/banners/app_banner_manager.cc
diff --git a/chrome/browser/banners/app_banner_manager.cc b/chrome/browser/banners/app_banner_manager.cc
index 6fdd5cf1c0fea885c956f7c3bb58acf210e62c43..d43b72291795cf564feb89e38bca752ac4765ffa 100644
--- a/chrome/browser/banners/app_banner_manager.cc
+++ b/chrome/browser/banners/app_banner_manager.cc
@@ -6,6 +6,7 @@
 
 #include "base/metrics/field_trial.h"
 #include "chrome/browser/banners/app_banner_data_fetcher.h"
+#include "chrome/browser/banners/app_banner_debug_log.h"
 #include "chrome/browser/banners/app_banner_settings_helper.h"
 #include "content/public/browser/navigation_details.h"
 #include "content/public/browser/render_frame_host.h"
@@ -49,8 +50,11 @@ void AppBannerManager::DidFinishLoad(
 
   // A secure scheme is required to show banners, so exit early if we see the
   // URL is invalid.
-  if (!validated_url.SchemeIsSecure() && !gDisableSecureCheckForTesting)
+  if (!validated_url.SchemeIsSecure() && !gDisableSecureCheckForTesting) {
+    SendDebugMessage(web_contents(),
+                     "not shown: page not served over secure scheme");

[benwells, 2015/05/11 08:08:40]

FYI this is about to go out of date. To match the next version say something
like 'from a secure origin.'

[dominickn (DO NOT USE), 2015/05/12 07:41:31]

Done.

     return;
+  }
 
   // Kick off the data retrieval pipeline.
   data_fetcher_ = CreateAppBannerDataFetcher(weak_factory_.GetWeakPtr(),