extensions: Abstract out install delay strategy

chrome/browser/extensions/extension_garbage_collector.cc

 // Copyright 2014 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/extensions/extension_garbage_collector.h"
 
 #include <stddef.h>
 
 #include <memory>
 #include <utility>
@@ skipping 216 matching lines @@
        iter != extensions->end();
        ++iter) {
     if (AppIsolationInfo::HasIsolatedStorage(iter->get())) {
       active_paths->insert(
           content::BrowserContext::GetStoragePartitionForSite(
               context_, util::GetSiteForExtensionId((*iter)->id(), context_))
               ->GetPath());
     }
   }
 
-  ExtensionService* service =
-      ExtensionSystem::Get(context_)->extension_service();
-  service->OnGarbageCollectIsolatedStorageStart();
+  DCHECK(!installs_delayed_for_gc_);
+  installs_delayed_for_gc_ = true;
   content::BrowserContext::GarbageCollectStoragePartitions(
       context_, std::move(active_paths),
-      base::Bind(&ExtensionService::OnGarbageCollectIsolatedStorageFinished,
-                 service->AsWeakPtr()));
+      base::Bind(
+          &ExtensionGarbageCollector::OnGarbageCollectIsolatedStorageFinished,
+          weak_factory_.GetWeakPtr()));
+}
+
+void ExtensionGarbageCollector::OnGarbageCollectIsolatedStorageFinished() {
+  DCHECK(installs_delayed_for_gc_);
+  installs_delayed_for_gc_ = false;
+
+  ExtensionSystem::Get(context_)
+      ->extension_service()
+      ->MaybeFinishDelayedInstallations();
 }
 
 void ExtensionGarbageCollector::OnBeginCrxInstall(
     const std::string& extension_id) {
   crx_installs_in_progress_++;
 }
 
 void ExtensionGarbageCollector::OnFinishCrxInstall(
     const std::string& extension_id,
     bool success) {
   crx_installs_in_progress_--;
   if (crx_installs_in_progress_ < 0) {
     // This can only happen if there is a mismatch in our begin/finish
     // accounting.
     NOTREACHED();
 
     // Don't let the count go negative to avoid garbage collecting when
     // an install is actually in progress.
     crx_installs_in_progress_ = 0;
   }
 }
 
+InstallGate::Action ExtensionGarbageCollector::ShouldDelay(
+    const Extension* extension,
+    bool install_immediately) {
+  return installs_delayed_for_gc_ ? DELAY : INSTALL;
+}
+
 }  // namespace extensions