[Reland] Refactor WebappRegistry into a singleton instance.

chrome/browser/browsing_data/browsing_data_remover_unittest.cc

 // Copyright (c) 2012 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/browsing_data/browsing_data_remover.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <list>
@@ skipping 300 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(TestStoragePartition);
 };
 
 #if BUILDFLAG(ANDROID_JAVA_UI)
 class TestWebappRegistry : public WebappRegistry {
  public:
   TestWebappRegistry() : WebappRegistry() { }
 
   void UnregisterWebappsForUrls(
-      const base::Callback<bool(const GURL&)>& url_filter,
-      const base::Closure& callback) override {
-    // Mocks out a JNI call and runs the callback as a delayed task.
-    BrowserThread::PostDelayedTask(BrowserThread::UI, FROM_HERE, callback,
-                                   base::TimeDelta::FromMilliseconds(10));
+      const base::Callback<bool(const GURL&)>& url_filter) override {
+    // Mocks out a JNI call.
   }
 
   void ClearWebappHistoryForUrls(
-      const base::Callback<bool(const GURL&)>& url_filter,
-      const base::Closure& callback) override {
-    // Mocks out a JNI call and runs the callback as a delayed task.
-    BrowserThread::PostDelayedTask(BrowserThread::UI, FROM_HERE, callback,
-                                   base::TimeDelta::FromMilliseconds(10));
+      const base::Callback<bool(const GURL&)>& url_filter) override {
+    // Mocks out a JNI call.
   }
 };
 #endif
 
 // Custom matcher to test the equivalence of two URL filters. Since those are
 // blackbox predicates, we can only approximate the equivalence by testing
 // whether the filter give the same answer for several URLs. This is currently
 // good enough for our testing purposes, to distinguish whitelists
 // and blacklists, empty and non-empty filters and such.
 // TODO(msramek): BrowsingDataRemover and some of its backends support URL
@@ skipping 2697 matching lines @@
   EXPECT_TRUE(remover->is_removing());
 
   // Add one more deletion and wait for it.
   BlockUntilBrowsingDataRemoved(
       browsing_data::ALL_TIME,
       BrowsingDataRemover::REMOVE_COOKIES,
       BrowsingDataHelper::UNPROTECTED_WEB);
 
   EXPECT_FALSE(remover->is_removing());
 }