Create ExtensionSystemImpl::quota_service_ before loading any extension

chrome/browser/extensions/extension_system_impl.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_system_impl.h"
 
 #include <algorithm>
 
 #include "base/base_switches.h"
 #include "base/bind.h"
@@ skipping 257 matching lines @@
       base::ThreadRestrictions::ScopedAllowIO allow_io;
       extension_service_->component_loader()->AddOrReplace(
           base::FilePath(t.token()));
     }
   }
 
   app_sorting_.reset(new ChromeAppSorting(profile_));
 
   InitInstallGates();
 
+  // ExtensionService::Init() might finish loading a component extension before

[Devlin, 2016/11/22 16:02:20]

Could we shorten this to simply:
// Extension API calls require the QuotaService, so create it before
// loading any extensions.
?

On that note, I also wonder if we should move this instantiation above loading
component extensions.  In reality, it *probably* doesn't matter much, since any
API call from the renderer will be after we finish this (and component
extensions don't report load errors modally), but that seems like a fragile
guarantee.  And the QuotaService is nearly free to construct.  WDYT?

[lazyboy, 2016/11/22 19:33:30]

Done.
Sounds good, done.

+  // Init() completes, e.g. when Init() is blocked showing an extension load
+  // error. In that case extension API call from any component extension can
+  // arrive at ExtensionFunctionDispatcher, which will access |quota_service_|.
+  // So initialize |quota_service_| before calling Init().
+  quota_service_.reset(new QuotaService);
+
   extension_service_->Init();
 
   // Make sure ExtensionSyncService is created.
   ExtensionSyncService::Get(profile_);
 
   // Make the chrome://extension-icon/ resource available.
   content::URLDataSource::Add(profile_, new ExtensionIconSource(profile_));
-
-  quota_service_.reset(new QuotaService);
 }
 
 void ExtensionSystemImpl::Shared::Shutdown() {
   if (content_verifier_.get())
     content_verifier_->Shutdown();
   if (extension_service_)
     extension_service_->Shutdown();
 }
 
 ServiceWorkerManager* ExtensionSystemImpl::Shared::service_worker_manager() {
@@ skipping 173 matching lines @@
 void ExtensionSystemImpl::UnregisterExtensionWithRequestContexts(
     const std::string& extension_id,
     const UnloadedExtensionInfo::Reason reason) {
   BrowserThread::PostTask(
       BrowserThread::IO,
       FROM_HERE,
       base::Bind(&InfoMap::RemoveExtension, info_map(), extension_id, reason));
 }
 
 }  // namespace extensions