Create the BackgroundFetchBatchManager and initiate a download.

content/browser/background_fetch/background_fetch_context.cc

 // Copyright 2017 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 "content/browser/background_fetch/background_fetch_context.h"
 
+#include "content/browser/background_fetch/batch_request.h"
 #include "content/browser/background_fetch/fetch_request.h"
 #include "content/browser/service_worker/service_worker_context_wrapper.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/download_manager.h"
 #include "content/public/browser/storage_partition.h"
 
 namespace content {
 
 BackgroundFetchContext::BackgroundFetchContext(
     BrowserContext* browser_context,
+    StoragePartition* storage_partition,
     const scoped_refptr<ServiceWorkerContextWrapper>& service_worker_context)
     : service_worker_context_(service_worker_context),
+      background_fetch_batch_manager_(browser_context, storage_partition),
       background_fetch_data_manager_(this) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   // TODO(harkness): BackgroundFetchContext should have
   // ServiceWorkerContextObserver as a parent class and should register as an
   // observer here.
 }
 
 BackgroundFetchContext::~BackgroundFetchContext() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 }
 
 void BackgroundFetchContext::Init() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   // TODO(harkness): Create the Download observer.
-  // TODO(harkness): Create the Batch manager.
 }
 
 void BackgroundFetchContext::Shutdown() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 }
 
-void BackgroundFetchContext::CreateRequest(const FetchRequest& fetch_request) {
+void BackgroundFetchContext::CreateRequest(
+    const BatchRequest& batch_request,
+    const std::vector<FetchRequest>& fetch_requests) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);

[Peter Beverloo, 2017/02/24 02:05:15]

qq: why UI?

[harkness, 2017/02/24 11:47:10]

Left over from an initial plan. Once I move the Data/Batch managers to the IO
thread entirely as you suggested, this will be a IO check, but for now I'm just
going to remove it.

+  DCHECK_GE(1U, fetch_requests.size());
   // Inform the data manager about the new download.
-  background_fetch_data_manager_.CreateRequest(fetch_request);
+  BackgroundFetchDataManager::BatchData* batch_data =
+      background_fetch_data_manager_.CreateRequest(batch_request,
+                                                   fetch_requests);
+  DCHECK(batch_data);

[Peter Beverloo, 2017/02/24 02:05:15]

We shouldn't crash the entire browser when a Service Worker creates two
background fetches having the same tag.

[harkness, 2017/02/24 11:47:10]

Good point, and the error logging is already done in the Data manager. 

 
-  // TODO(harkness): Make the request to the download manager.
+  background_fetch_batch_manager_.ProcessBatch(batch_request.guid(),
+                                               batch_data);
 }
 
 }  // namespace content