Implement a poor man's PostAfterStartupTask() function.

chrome/browser/chrome_content_browser_client.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 "chrome/browser/chrome_content_browser_client.h"
 
 #include <set>
 #include <utility>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/files/scoped_file.h"
 #include "base/i18n/icu_util.h"
 #include "base/lazy_instance.h"
 #include "base/path_service.h"
 #include "base/prefs/pref_service.h"
 #include "base/prefs/scoped_user_pref_update.h"
+#include "base/rand_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/sequenced_worker_pool.h"
+#include "base/time/time.h"
 #include "chrome/browser/browser_about_handler.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_shutdown.h"
 #include "chrome/browser/browsing_data/browsing_data_helper.h"
 #include "chrome/browser/browsing_data/browsing_data_remover.h"
 #include "chrome/browser/character_encoding.h"
+#include "chrome/browser/chrome_browser_main.h"
 #include "chrome/browser/chrome_content_browser_client_parts.h"
 #include "chrome/browser/chrome_net_benchmarking_message_filter.h"
 #include "chrome/browser/chrome_quota_permission_context.h"
 #include "chrome/browser/content_settings/cookie_settings.h"
 #include "chrome/browser/content_settings/tab_specific_content_settings.h"
 #include "chrome/browser/defaults.h"
 #include "chrome/browser/download/download_prefs.h"
 #include "chrome/browser/font_family_cache.h"
 #include "chrome/browser/geolocation/chrome_access_token_store.h"
 #include "chrome/browser/geolocation/geolocation_permission_context.h"
@@ skipping 764 matching lines @@
 
 #if defined(USE_X11)
   main_parts->AddParts(new ChromeBrowserMainExtraPartsX11());
 #endif
 
   chrome::AddMetricsExtraParts(main_parts);
 
   return main_parts;
 }
 
+namespace {
+void PostAfterStartupTaskImpl(
+    const tracked_objects::Location& from_here,
+    const scoped_refptr<base::TaskRunner>& task_runner,
+    const base::Closure& task) {
+  if (!chrome::IsBrowserStartupComplete()) {
+    const int kMinDelay = 5;
+    const int kMaxDelay = 30;
+    task_runner->PostDelayedTask(
+        FROM_HERE,
+        base::Bind(PostAfterStartupTaskImpl,
+                   from_here, task_runner, task),
+        base::TimeDelta::FromSeconds(base::RandInt(kMinDelay, kMaxDelay)));
+    return;
+  }
+  task_runner->PostTask(from_here, task);

[jam, 2015/03/10 23:04:34]

It seems simpler that the code below would pass all these tasks to the same
header that has IsStartupComplete, and that code would accumulate all the tasks
into a vector that it then runs when it's been told that startup is complete

[michaeln, 2015/03/10 23:54:54]

Is it? We'd need a thread safe collection somewhere to hold the tasks. Alloc'ing
storage for the collection and then synchronizing access to it seemed less
simple to me. Having said that, i'd be fine with switching over to something
along those lines, but it's not an obvious improvement to me.

[jam, 2015/03/23 23:19:44]

sure, but given that only a few places should/will call this, using a lock won't
be expensive.
I would prefer seeing that because I think reposting every task after a random
5-30s interval is extra complexity which isn't clear to me that it's needed

[michaeln, 2015/03/24 23:01:11]

Done. There is still a polling timer but only one for all of these tasks. Also
avoided using a lock.

+}
+}
+
+void ChromeContentBrowserClient::PostAfterStartupTask(
+    const tracked_objects::Location& from_here,
+    const scoped_refptr<base::TaskRunner>& task_runner,
+    const base::Closure& task) {
+  PostAfterStartupTaskImpl(from_here, task_runner, task);

[gab, 2015/03/10 15:00:32]

Why does this need an explicit impl? i.e. why not handle the call right here?

[michaeln, 2015/03/10 19:46:26]

good question, this method can be called on anythread and in the called before
startup case the bind closure wants a weakptr to 'this', but that runs afould of
weakptr thread safefy checks

[gab, 2015/03/10 19:55:27]

ChromeContentBrowserClient has a weak_factory_, can't you just use
weak_factory_.GetWeakPtr() for |this|?

(and also clarify in the API that this tasks will exhibit SKIP_ON_SHUTDOWN
behavior (as any delayed task do in TaskRunners FWIW))

[michaeln, 2015/03/10 23:54:54]

nope, weakptrs have thread affinity
https://code.google.com/p/chromium/codesearch#chromium/src/base/memory/weak_p...

[michaeln, 2015/03/24 23:01:11]

initialized a weak_this_ ptr in the constructor

+}
+
 std::string ChromeContentBrowserClient::GetStoragePartitionIdForSite(
     content::BrowserContext* browser_context,
     const GURL& site) {
   std::string partition_id;
 
   // The partition ID for webview guest processes is the string value of its
   // SiteInstance URL - "chrome-guest://app_id/persist?partition".
   if (site.SchemeIs(content::kGuestScheme)) {
     partition_id = site.spec();
   } else if (site.GetOrigin().spec() == kChromeUIChromeSigninURL) {
@@ skipping 1819 matching lines @@
       switches::kDisableWebRtcEncryption,
     };
     to_command_line->CopySwitchesFrom(from_command_line,
                                       kWebRtcDevSwitchNames,
                                       arraysize(kWebRtcDevSwitchNames));
   }
 }
 #endif  // defined(ENABLE_WEBRTC)
 
 }  // namespace chrome