Implement a poor man's PostAfterStartupTask() function.

content/browser/appcache/appcache_update_job.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 "content/browser/appcache/appcache_update_job.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/compiler_specific.h"
 #include "base/message_loop/message_loop.h"
 #include "base/profiler/scoped_tracker.h"
+#include "base/rand_util.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "content/browser/appcache/appcache_group.h"
 #include "content/browser/appcache/appcache_histograms.h"
+#include "content/public/browser/browser_main_runner.h"
 #include "net/base/io_buffer.h"
 #include "net/base/load_flags.h"
 #include "net/base/net_errors.h"
 #include "net/base/request_priority.h"
 #include "net/http/http_request_headers.h"
 #include "net/http/http_response_headers.h"
 #include "net/url_request/url_request_context.h"
 
 namespace content {
 
@@ skipping 338 matching lines @@
     : service_(service),
       manifest_url_(group->manifest_url()),
       group_(group),
       update_type_(UNKNOWN_TYPE),
       internal_state_(FETCH_MANIFEST),
       master_entries_completed_(0),
       url_fetches_completed_(0),
       manifest_fetcher_(NULL),
       manifest_has_valid_mime_type_(false),
       stored_state_(UNSTORED),
-      storage_(service->storage()) {
+      storage_(service->storage()),
+      weak_factory_(this) {
     service_->AddObserver(this);
 }
 
 AppCacheUpdateJob::~AppCacheUpdateJob() {
   if (service_)
     service_->RemoveObserver(this);
   if (internal_state_ != COMPLETED)
     Cancel();
 
   DCHECK(!manifest_fetcher_);
@@ skipping 59 matching lines @@
     update_type_ = CACHE_ATTEMPT;
     DCHECK(host);
     NotifySingleHost(host, APPCACHE_CHECKING_EVENT);
   }
 
   if (!new_master_resource.is_empty()) {
     AddMasterEntryToFetchList(host, new_master_resource,
                               is_new_pending_master_entry);
   }
 
+  DelayableStart();
+}
+
+void AppCacheUpdateJob::DelayableStart() {
+  if (IsBrowserStartingUp()) {
+    // Defer running update jobs till after startup.
+    delayed_start_timer_.Start(
+        FROM_HERE, base::TimeDelta::FromSeconds(base::RandInt(5, 15)),

[cmumford, 2015/02/26 23:47:45]

Constants for 5 & 15?

Also (I don't know RandInt well), but do we need to see the random number
generator to avoid getting the same value at startup?

+        base::Bind(&AppCacheUpdateJob::DelayableStart,
+                   weak_factory_.GetWeakPtr()));
+    return;
+  }
   FetchManifest(true);
 }
 
 AppCacheResponseWriter* AppCacheUpdateJob::CreateResponseWriter() {
   AppCacheResponseWriter* writer =
       storage_->CreateResponseWriter(manifest_url_,
                                                 group_->group_id());
   stored_response_ids_.push_back(writer->response_id());
   return writer;
 }
@@ skipping 1157 matching lines @@
 
   // Break the connection with the group so the group cannot call delete
   // on this object after we've posted a task to delete ourselves.
   group_->SetUpdateAppCacheStatus(AppCacheGroup::IDLE);
   group_ = NULL;
 
   base::MessageLoop::current()->DeleteSoon(FROM_HERE, this);
 }
 
 }  // namespace content