Implement server-suggested update check backoff

chrome/browser/android/webapk/webapk_installer.cc

Index: chrome/browser/android/webapk/webapk_installer.cc
diff --git a/chrome/browser/android/webapk/webapk_installer.cc b/chrome/browser/android/webapk/webapk_installer.cc
index 7df48b20facd97280314ca703e2ea27735ab8632..93f7ab95c4a4d75fd3f25ce6bba6602defe4ee2e 100644
--- a/chrome/browser/android/webapk/webapk_installer.cc
+++ b/chrome/browser/android/webapk/webapk_installer.cc
@@ -353,6 +353,7 @@ WebApkInstaller::WebApkInstaller(content::BrowserContext* browser_context,
       server_url_(GetServerUrl()),
       webapk_download_url_timeout_ms_(kWebApkDownloadUrlTimeoutMs),
       download_timeout_ms_(kDownloadTimeoutMs),
+      relax_updates_(false),

[pkotwicz, 2017/03/04 00:20:47]

Nit: Can you initialize |webapk_version_| ?

[Xi Han, 2017/03/06 22:14:21]

Done.

       task_type_(UNDEFINED),
       weak_ptr_factory_(this) {
   CreateJavaRef();
@@ -420,9 +421,10 @@ void WebApkInstaller::OnURLFetchComplete(const net::URLFetcher* source) {
   }
 
   GURL signed_download_url(response->signed_download_url());
-  // https://crbug.com/680131. The server sends an empty URL if the server does
-  // not have a newer WebAPK to update to.
   if (task_type_ == UPDATE && signed_download_url.is_empty()) {
+    relax_updates_ = response->relax_updates();

[pkotwicz, 2017/03/04 00:20:47]

Nit: Move the setting of |relax_updates_| after the comment

[Xi Han, 2017/03/06 22:14:21]

Done.

+    // https://crbug.com/680131. The server sends an empty URL if the server
+    // does not have a newer WebAPK to update to.
     OnSuccess();
     return;
   }
@@ -627,11 +629,11 @@ void WebApkInstaller::OnTimeout() {
 }
 
 void WebApkInstaller::OnSuccess() {
-  finish_callback_.Run(true, webapk_package_);
+  finish_callback_.Run(true, relax_updates_, webapk_package_);
   delete this;
 }
 
 void WebApkInstaller::OnFailure() {
-  finish_callback_.Run(false, webapk_package_);
+  finish_callback_.Run(false, relax_updates_, webapk_package_);
   delete this;
 }