Fix test slowness introduced by https://codereview.chromium.org/2771793003

chrome/browser/android/webapk/webapk_icon_hasher.h

 // 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.
 
 #ifndef CHROME_BROWSER_ANDROID_WEBAPK_WEBAPK_ICON_HASHER_H_
 #define CHROME_BROWSER_ANDROID_WEBAPK_WEBAPK_ICON_HASHER_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 17 matching lines @@
   // Creates a self-owned WebApkIconHasher instance. The instance downloads
   // |icon_url| and calls |callback| with the Murmur2 hash of the downloaded
   // image. The hash is taken over the raw image bytes (no image
   // encoding/decoding beforehand). |callback| is called with an empty string if
   // the image cannot not be downloaded in time (e.g. 404 HTTP error code).
   static void DownloadAndComputeMurmur2Hash(
       net::URLRequestContextGetter* request_context_getter,
       const GURL& icon_url,
       const Murmur2HashCallback& callback);
 
- private:
-  WebApkIconHasher(
+  static void DownloadAndComputeMurmur2HashWithTimeout(
       net::URLRequestContextGetter* request_context_getter,
       const GURL& icon_url,
+      int timeout_ms,
       const Murmur2HashCallback& callback);
+
+ private:
+  WebApkIconHasher(net::URLRequestContextGetter* request_context_getter,
+                   const GURL& icon_url,
+                   int timeout_ms,
+                   const Murmur2HashCallback& callback);
   ~WebApkIconHasher() override;
 
   // net::URLFetcherDelegate:
   void OnURLFetchComplete(const net::URLFetcher* source) override;
 
   // Called if downloading the icon takes too long.
   void OnDownloadTimedOut();
 
   // Calls |callback_| with |icon_murmur2_hash|. Also deletes the instance.
   void RunCallback(const std::string& icon_murmur2_hash);
 
   // Called with the image hash.
   Murmur2HashCallback callback_;
 
   std::unique_ptr<net::URLFetcher> url_fetcher_;
 
   // Fails WebApkIconHasher if the download takes too long.
   base::OneShotTimer download_timeout_timer_;
 
   DISALLOW_COPY_AND_ASSIGN(WebApkIconHasher);
 };
 
 #endif  // CHROME_BROWSER_ANDROID_WEBAPK_WEBAPK_ICON_HASHER_H_