Allow the app banner installability check to run on page load.

chrome/browser/installable/installable_manager.h

 // Copyright 2016 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.
 
 #ifndef CHROME_BROWSER_INSTALLABLE_INSTALLABLE_MANAGER_H_
 #define CHROME_BROWSER_INSTALLABLE_INSTALLABLE_MANAGER_H_
 
 #include <map>
 #include <memory>
 #include <tuple>
 #include <utility>
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "chrome/browser/installable/installable_logging.h"
+#include "chrome/browser/installable/installable_metrics.h"
 #include "content/public/browser/service_worker_context.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
 #include "content/public/common/manifest.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "url/gurl.h"
 
 // This struct specifies the work to be done by the InstallableManager.
 // Data is cached and fetched in the order specified in this struct. A web app
 // manifest will always be fetched first.
@@ skipping 92 matching lines @@
   // Get the installable data, fetching the resources specified in |params|.
   // |callback| is invoked synchronously (i.e. no via PostTask on the UI thread
   // when the data is ready; the synchronous execution ensures that the
   // references |callback| receives in its InstallableData argument are valid.
   //
   // Calls requesting data that is already fetched will return the cached data.
   // This method is marked virtual so clients may mock this object in tests.
   virtual void GetData(const InstallableParams& params,
                        const InstallableCallback& callback);
 
+  // Called via AppBannerManagerAndroid to record metrics on how often the
+  // installable check is completed when the menu or add to homescreen menu item
+  // is opened on Android.
+  void RecordMenuOpenHistogram();
+  void RecordMenuItemAddToHomescreenHistogram();
+
  private:
+  friend class InstallableManagerBrowserTest;
   friend class InstallableManagerUnitTest;
   FRIEND_TEST_ALL_PREFIXES(InstallableManagerBrowserTest,
                            ManagerBeginsInEmptyState);
   FRIEND_TEST_ALL_PREFIXES(InstallableManagerBrowserTest, CheckWebapp);
 
   using Task = std::pair<InstallableParams, InstallableCallback>;
   using IconParams = std::tuple<int, int, content::Manifest::Icon::IconPurpose>;
 
   struct ManifestProperty;
   struct InstallableProperty;
@@ skipping 69 matching lines @@
   bool is_installable() const;
 
   // The list of <params, callback> pairs that have come from a call to GetData.
   std::vector<Task> tasks_;
 
   // Installable properties cached on this object.
   std::unique_ptr<ManifestProperty> manifest_;
   std::unique_ptr<InstallableProperty> installable_;
   std::map<IconParams, IconProperty> icons_;
 
+  // A representation of the progress of the PWA check. This is reset per
+  // navigation and is independent of the caching mechanism, i.e. if a PWA check
+  // is run multiple times, this will be set on the first run.
+  InstallableMetrics::InstallabilityCheckStatus status_;

[benwells, 2017/03/30 08:22:37]

This variable is kinda subtle (e.g. you need to comment). Can you rename it to
something making the subtelty obviuos? E.g. first_run_status_, page_status_, or
something like that.

[dominickn, 2017/03/30 23:42:53]

Done.

+
+  // Counts for the number of queued requests of the menu and add to homescreen
+  // menu item there have been whilst the installable check is awaiting
+  // completion. Used for metrics recording.
+  int menu_opened_count_;
+  int menu_item_add_to_homescreen_count_;
+
   bool is_active_;
 
   base::WeakPtrFactory<InstallableManager> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(InstallableManager);
 };
 
 #endif  // CHROME_BROWSER_INSTALLABLE_INSTALLABLE_MANAGER_H_