Fall back to shortcut A2HS when Phonesky is out of date or unavailable.

chrome/browser/android/webapk/webapk_installer.cc

 // 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.
 
 #include "chrome/browser/android/webapk/webapk_installer.h"
 
 #include "base/android/build_info.h"
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
 #include "base/android/path_utils.h"
@@ skipping 409 matching lines @@
 
   GURL signed_download_url(response->signed_download_url());
   if (!signed_download_url.is_valid() || response->package_name().empty()) {
     OnFailure();
     return;
   }
 
   if (CanUseGooglePlayInstallService()) {
     int version = 1;
     base::StringToInt(response->version(), &version);
-    if (!InstallOrUpdateWebApkFromGooglePlay(
-        response->package_name(), version, response->token())) {
-      OnFailure();
-    }
+    // TODO(hanxi): crbug.com/688759. Removes the return value of
+    // |InstallOrUpdateWebApkFromGooglePlay()| which is executed asynchronously.

[pkotwicz, 2017/02/05 02:13:55]

Nits:
"Removes" -> "Remove"
"|InstallOrUpdateWebApkFromGooglePlay()|" ->
"InstallOrUpdateWebApkFromGooglePlay()"
"which is" -> "is"

[Xi Han, 2017/02/06 18:03:44]

How about "Remove the return value of InstallOrUpdateWebApkFromGooglePlay(),
since a callback will be called after the install or update is either failed or
completed."?

[pkotwicz, 2017/02/06 23:12:12]

One small nit: "is either" -> "has either"
Otherwise looks good

[Xi Han, 2017/02/07 02:52:10]

Done.

+    InstallOrUpdateWebApkFromGooglePlay(
+        response->package_name(), version, response->token());
     return;
   }
 
   OnGotWebApkDownloadUrl(signed_download_url, response->package_name());
 }
 
 void WebApkInstaller::DownloadAppIconAndComputeMurmur2Hash() {
   // Safeguard. WebApkIconHasher crashes if asked to fetch an invalid URL.
   if (!shortcut_info_.best_icon_url.is_valid()) {
     OnFailure();
@@ skipping 176 matching lines @@
 
 void WebApkInstaller::OnSuccess() {
   finish_callback_.Run(true, webapk_package_);
   delete this;
 }
 
 void WebApkInstaller::OnFailure() {
   finish_callback_.Run(false, webapk_package_);
   delete this;
 }