Initialize TaskScheduler in all child processes.

content/child/child_process.h

Index: content/child/child_process.h
diff --git a/content/child/child_process.h b/content/child/child_process.h
index 9a56e76928b34a24f42e56ffb16b9bdb0d34a396..ecc8a7fe16b5803ef99a96b77cd19366bbf7e309 100644
--- a/content/child/child_process.h
+++ b/content/child/child_process.h
@@ -79,6 +79,10 @@ class CONTENT_EXPORT ChildProcess {
 
   static void WaitForDebugger(const std::string& label);
  private:
+  // Initializes TaskScheduler. May be overridden to initialize TaskScheduler
+  // with custom arguments.
+  virtual void InitializeTaskScheduler();
+
   int ref_count_;
 
   // An event that will be signalled when we shutdown.
@@ -92,6 +96,9 @@ class CONTENT_EXPORT ChildProcess {
   // io_thread_.
   std::unique_ptr<ChildThreadImpl> main_thread_;
 
+  // Whether this ChildProcess initialized TaskScheduler.
+  bool initialized_task_scheduler_ = false;
+
   DISALLOW_COPY_AND_ASSIGN(ChildProcess);
 };