Connect Mojo budget_service to BudgetManager implementation of Reserve.

chrome/browser/budget_service/budget_service_impl.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/budget_service/budget_service_impl.h"
 
 #include "chrome/browser/budget_service/budget_manager.h"
 #include "chrome/browser/budget_service/budget_manager_factory.h"
 #include "chrome/browser/profiles/profile.h"
 #include "content/public/browser/render_process_host.h"
@@ skipping 37 matching lines @@
   DCHECK(host);
 
   // Query the BudgetManager for the budget.
   content::BrowserContext* context = host->GetBrowserContext();
   BudgetManagerFactory::GetForProfile(context)->GetBudget(origin, callback);
 }
 
 void BudgetServiceImpl::Reserve(const url::Origin& origin,
                                 blink::mojom::BudgetOperationType operation,
                                 const ReserveCallback& callback) {
-  // TODO(harkness): Call the BudgetManager::Reserve when it is available.
-  callback.Run(blink::mojom::BudgetServiceErrorType::NONE, false);
+  // The RenderProcessHost should still be alive as long as any connections are
+  // alive, and if the BudgetService mojo connection is down, the
+  // BudgetServiceImpl should have been destroyed.
+  content::RenderProcessHost* host =
+      content::RenderProcessHost::FromID(render_process_id_);
+  DCHECK(host);
+
+  // Request a reservation from the BudgetManager.
+  content::BrowserContext* context = host->GetBrowserContext();
+  BudgetManagerFactory::GetForProfile(context)->Reserve(origin, operation,
+                                                        callback);
 }