Do not create WebAPK via add-to-homescreen menu item if manifest is not WebAPK-compatible

This CL prevents creating WebAPKs via the add-to-homescreen menu item:
- If the Web Manifest does not contain any icons
- If any URL in the Web Manifest contains a username and password

This makes the logic in add_to_homescreen_data_fetcher.cc match the logic in
app_banner_manager_android.cc

BUG=648491
TEST=None

Review-Url: https://codereview.chromium.org/2349263003
Cr-Commit-Position: refs/heads/master@{#419949}

chrome/browser/android/webapps/add_to_homescreen_data_fetcher.cc

@@ -12,6 +12,7 @@
 #include "base/strings/string16.h"
 #include "chrome/browser/android/offline_pages/offline_page_utils.h"
 #include "chrome/browser/android/shortcut_helper.h"
+#include "chrome/browser/android/webapk/webapk_web_manifest_checker.h"
 #include "chrome/browser/favicon/favicon_service_factory.h"
 #include "chrome/browser/installable/installable_manager.h"
 #include "chrome/browser/manifest/manifest_icon_selector.h"
@@ -205,8 +206,12 @@ void AddToHomescreenDataFetcher::OnDidPerformInstallableCheck(
 
   is_installable_check_complete_ = true;
 
-  if (check_webapk_compatibility_)
-    weak_observer_->OnDidDetermineWebApkCompatibility(data.is_installable);
+  if (check_webapk_compatibility_) {
+    bool webapk_compatible =
+        (data.error_code == NO_ERROR_DETECTED &&
+         AreWebManifestUrlsWebApkCompatible(data.manifest));
+    weak_observer_->OnDidDetermineWebApkCompatibility(webapk_compatible);
+  }
 
   if (!data.manifest.IsEmpty()) {
     content::RecordAction(