Allow only responsive websites to install as a web app on mobile.

chrome/browser/banners/app_banner_data_fetcher.cc

Index: chrome/browser/banners/app_banner_data_fetcher.cc
diff --git a/chrome/browser/banners/app_banner_data_fetcher.cc b/chrome/browser/banners/app_banner_data_fetcher.cc
index 8f973ce45678d382aa8013f8ff63d597bc113674..47fb71972393d74a92e7c9d48c8c1d25c4a27b79 100644
--- a/chrome/browser/banners/app_banner_data_fetcher.cc
+++ b/chrome/browser/banners/app_banner_data_fetcher.cc
@@ -70,9 +70,10 @@ AppBannerDataFetcher::AppBannerDataFetcher(
     base::WeakPtr<Delegate> delegate,
     int ideal_icon_size)
     : WebContentsObserver(web_contents),
+      is_active_(false),
+      is_responsive_(true),

[benwells, 2015/05/27 05:58:55]

I think this can be made cleaner. In particular we don't need the is_responsive_
field (which is kind of falsely set to true on desktop) and to have the Start
method overridden / called later.

Given we may want to check responsiveness differently depending native /
webbiness, maybe we should do it after that has been determined. That is, there
would be a new function called something like
'CheckResponsiveness(base::Callback... then)'. In the base fetcher this would
just call then, but in the android one in would do the meta tag checks etc.

[dominickn (DO NOT USE), 2015/06/05 07:42:59]

Done, but slightly differently to your suggestion.

       ideal_icon_size_(ideal_icon_size),
       weak_delegate_(delegate),
-      is_active_(false),
       event_request_id_(-1) {
 }
 
@@ -259,6 +260,13 @@ void AppBannerDataFetcher::OnDidGetManifest(
     return;
   }
 
+  if (!is_responsive_) {
+    OutputDeveloperMetaViewportErrorMessage(web_contents,
+                                            kMetaViewportTagNotResponsive);
+    Cancel();
+    return;
+  }
+
   banners::TrackDisplayEvent(DISPLAY_EVENT_BANNER_REQUESTED);
 
   web_app_data_ = manifest;