Make sure the Async test cases availabel today generate correct ClientID.

chrome/browser/ui/webui/offline_internals_ui.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/ui/webui/offline_internals_ui.h"
 
 #include <stdint.h>
 #include <stdlib.h>
 #include <vector>
 
 #include "base/bind.h"
+#include "base/guid.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/android/offline_pages/offline_page_model_factory.h"
 #include "chrome/browser/android/offline_pages/request_coordinator_factory.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/url_constants.h"
 #include "components/offline_pages/background/request_coordinator.h"
 #include "components/offline_pages/background/save_page_request.h"
@@ skipping 307 matching lines @@
 }
 
 void OfflineInternalsUIMessageHandler::HandleAddToRequestQueue(
     const base::ListValue* args) {
   const base::Value* callback_id;
   CHECK(args->Get(0, &callback_id));
 
   std::string url;
   CHECK(args->GetString(1, &url));
 
+  // To be visible in Downloads UI, these items need a well-formed GUID
+  // and AsyncNamespace in their ClientId.
   std::ostringstream id_stream;
-  id_stream << std::rand();
+  id_stream << base::GenerateGUID();
 
   ResolveJavascriptCallback(
       *callback_id,
       base::FundamentalValue(
           request_coordinator_->SavePageLater(
               GURL(url),
               offline_pages::ClientId(offline_pages::kAsyncNamespace,
                                       id_stream.str()),
               true)));
 }
@@ skipping 65 matching lines @@
   html_source->AddResourcePath("offline_internals_browser_proxy.js",
                                IDR_OFFLINE_INTERNALS_BROWSER_PROXY_JS);
   html_source->SetDefaultResource(IDR_OFFLINE_INTERNALS_HTML);
 
   content::WebUIDataSource::Add(Profile::FromWebUI(web_ui), html_source);
 
   web_ui->AddMessageHandler(new OfflineInternalsUIMessageHandler());
 }
 
 OfflineInternalsUI::~OfflineInternalsUI() {}