Make OnDataTimedout and OnDidPerformInstallableCheck mutually exclusive.

chrome/browser/android/webapps/add_to_homescreen_data_fetcher.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 "chrome/browser/android/webapps/add_to_homescreen_data_fetcher.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 191 matching lines @@
   if (!is_icon_saved_) {
     badge_icon_.reset();
     CreateLauncherIcon(SkBitmap());
   }
 }
 
 void AddToHomescreenDataFetcher::OnDidPerformInstallableCheck(
     const InstallableData& data) {
   badge_icon_.reset();
 
-  if (!web_contents() || !weak_observer_)
+  if (!web_contents() || !weak_observer_ || is_installable_check_complete_)
     return;
 
   is_installable_check_complete_ = true;
 
   bool webapk_compatible = false;
   if (check_webapk_compatibility_) {
     webapk_compatible = (data.error_code == NO_ERROR_DETECTED &&
                          AreWebManifestUrlsWebApkCompatible(data.manifest));
     weak_observer_->OnDidDetermineWebApkCompatibility(webapk_compatible);
 
@@ skipping 121 matching lines @@
 void AddToHomescreenDataFetcher::NotifyObserver(const SkBitmap& primary_icon) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   if (!web_contents() || !weak_observer_ || is_icon_saved_)
     return;
 
   is_icon_saved_ = true;
   primary_icon_ = primary_icon;
   is_ready_ = true;
   weak_observer_->OnDataAvailable(shortcut_info_, primary_icon_, badge_icon_);
 }