Implement a poor man's PostAfterStartupTask() function.

chrome/browser/chrome_content_browser_client.cc

Index: chrome/browser/chrome_content_browser_client.cc
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index f3d767f5790f955d8df52b54a1ce038bf0a7c366..c0c48537803ef3894c8e009d31fe5398c2f77337 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -16,15 +16,18 @@
 #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"
@@ -695,6 +698,8 @@ ChromeContentBrowserClient::ChromeContentBrowserClient()
 #if defined(ENABLE_EXTENSIONS)
   extra_parts_.push_back(new ChromeContentBrowserClientExtensionsPart);
 #endif
+
+  weak_this_ = weak_factory_.GetWeakPtr();
 }
 
 ChromeContentBrowserClient::~ChromeContentBrowserClient() {
@@ -786,6 +791,41 @@ content::BrowserMainParts* ChromeContentBrowserClient::CreateBrowserMainParts(
   return main_parts;
 }
 
+void ChromeContentBrowserClient::PostAfterStartupTask(
+    const tracked_objects::Location& from_here,
+    const scoped_refptr<base::TaskRunner>& task_runner,
+    const base::Closure& task) {
+  if (IsBrowserStartupComplete()) {
+    task_runner->PostTask(from_here, task);
+    return;
+  }
+
+  if (!BrowserThread:: CurrentlyOn(BrowserThread::UI)) {
+    BrowserThread::PostTask(
+        BrowserThread::UI,
+        FROM_HERE,
+        base::Bind(&ChromeContentBrowserClient::PostAfterStartupTask,
+                   weak_this_, from_here, task_runner, task));
+    return;
+  }
+
+  if (after_startup_tasks_.empty()) {
+    BrowserThread::PostDelayedTask(
+        BrowserThread::UI,
+        FROM_HERE,
+        base::Bind(&ChromeContentBrowserClient::OnAfterStartupTasksTimer,
+                   weak_this_),
+        base::TimeDelta::FromSeconds(5));
+  }
+
+  // When the time comes, spread their execution over 30 seconds.
+  const int kMinDelay = 0;
+  const int kMaxDelay = 30;
+  after_startup_tasks_.push_back(base::Bind(
+      &base::TaskRunner::PostDelayedTask, task_runner, from_here, task,
+      base::TimeDelta::FromSeconds(base::RandInt(kMinDelay, kMaxDelay))));
+}
+
 std::string ChromeContentBrowserClient::GetStoragePartitionIdForSite(
     content::BrowserContext* browser_context,
     const GURL& site) {
@@ -2556,6 +2596,22 @@ void ChromeContentBrowserClient::OverridePageVisibilityState(
   }
 }
 
+void ChromeContentBrowserClient::OnAfterStartupTasksTimer() {
+  if (!IsBrowserStartupComplete()) {
+    BrowserThread::PostDelayedTask(
+        BrowserThread::UI,
+        FROM_HERE,
+        base::Bind(&ChromeContentBrowserClient::OnAfterStartupTasksTimer,
+                   weak_this_),
+        base::TimeDelta::FromSeconds(5));
+    return;
+  }
+
+  for (const auto& task : after_startup_tasks_)
+    task.Run();
+  after_startup_tasks_.clear();

[michaeln, 2015/03/25 01:09:32]

Oh, I think there's a problem with this? I think it requires that any refcounted
objects bound up in the 'task' given to PostAfterStartupTask to have a
threadsafe refcount because the final ref could be released on this thread
rather than the target thread. It's unlikely given the kMinDelay to kMaxDelay
involved.

I'll massage it to avoid that problem.

[michaeln, 2015/03/25 02:25:18]

Done

+}
+
 #if defined(ENABLE_WEBRTC)
 void ChromeContentBrowserClient::MaybeCopyDisableWebRtcEncryptionSwitch(
     base::CommandLine* to_command_line,