Retry WebAPK download if fails for the first time.

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 37df154bd8a3115e4a5972973c4ac9b6b9766e7b..52dc9965a840a4ef8ce3ad7835d393c91e8132ad 100644
--- a/chrome/browser/android/webapk/webapk_installer.cc
+++ b/chrome/browser/android/webapk/webapk_installer.cc
@@ -17,6 +17,7 @@
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/task_runner_util.h"
+#include "base/threading/platform_thread.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "chrome/browser/android/shortcut_helper.h"
 #include "chrome/browser/android/webapk/webapk.pb.h"
@@ -355,23 +356,38 @@ void WebApkInstaller::OnGotWebApkDownloadUrl(const GURL& download_url,
   // directory.
   // TODO(pkotwicz): Figure out when downloaded WebAPK should be deleted.
 
+  StartDownloadingWebApk(
+      output_dir.AppendASCII(webapk_package_), download_url, true);
+}
+
+void WebApkInstaller::StartDownloadingWebApk(const base::FilePath& output_path,

[pkotwicz, 2016/09/27 19:47:28]

Nit: Rename this function to DownloadWebApk()

I think that this function name is more consistent with OnWebApkDownloaded() ...
and your comment in the .h file

[Xi Han, 2016/09/27 20:53:31]

Done.

+                                             const GURL& download_url,
+                                             bool retry_if_fails) {
   timer_.Start(
       FROM_HERE, base::TimeDelta::FromMilliseconds(download_timeout_ms_),
       base::Bind(&WebApkInstaller::OnTimeout, weak_ptr_factory_.GetWeakPtr()));
 
-  base::FilePath output_path = output_dir.AppendASCII(webapk_package_);
   downloader_.reset(new FileDownloader(
       download_url, output_path, true, request_context_getter_,
       base::Bind(&WebApkInstaller::OnWebApkDownloaded,
-                 weak_ptr_factory_.GetWeakPtr(), output_path)));
+                 weak_ptr_factory_.GetWeakPtr(),
+                 output_path, download_url, retry_if_fails)));
 }
 
 void WebApkInstaller::OnWebApkDownloaded(const base::FilePath& file_path,
+                                         const GURL& download_url,
+                                         bool retry_if_fails,
                                          FileDownloader::Result result) {
   timer_.Stop();

[pkotwicz, 2016/09/27 19:47:28]

Nit: Maybe reset |downloader_| for clarity

[Xi Han, 2016/09/27 20:53:31]

Done.

 
   if (result != FileDownloader::DOWNLOADED) {
-    OnFailure();
+    if (!retry_if_fails) {
+      OnFailure();
+      return;
+    }
+
+    base::PlatformThread::Sleep(base::TimeDelta::FromSeconds(2));

[pkotwicz, 2016/09/27 19:47:28]

Use BrowserThread::PostDelayedTask() instead

[Xi Han, 2016/09/27 20:53:31]

Done.

+    StartDownloadingWebApk(file_path, download_url, false);
     return;
   }