Add support for specifying message loop type and thread priority for content mojo services

BUG=722527

Review-Url: https://codereview.chromium.org/2952603002
Cr-Commit-Position: refs/heads/master@{#480876}

content/common/service_manager/embedded_service_runner.cc

@@ -30,6 +30,8 @@ class EmbeddedServiceRunner::InstanceManager
       : name_(name.as_string()),
         factory_callback_(info.factory),
         use_own_thread_(!info.task_runner && info.use_own_thread),
+        message_loop_type_(info.message_loop_type),
+        thread_priority_(info.thread_priority),
         quit_closure_(quit_closure),
         quit_task_runner_(base::ThreadTaskRunnerHandle::Get()),
         service_task_runner_(info.task_runner) {
@@ -43,7 +45,10 @@ class EmbeddedServiceRunner::InstanceManager
     if (use_own_thread_ && !thread_) {
       // Start a new thread if necessary.
       thread_.reset(new base::Thread(name_));
-      thread_->Start();
+      base::Thread::Options options;
+      options.message_loop_type = message_loop_type_;
+      options.priority = thread_priority_;
+      thread_->StartWithOptions(options);
       service_task_runner_ = thread_->task_runner();
     }
 
@@ -133,6 +138,8 @@ class EmbeddedServiceRunner::InstanceManager
   const std::string name_;
   const ServiceInfo::ServiceFactory factory_callback_;
   const bool use_own_thread_;
+  base::MessageLoop::Type message_loop_type_;
+  base::ThreadPriority thread_priority_;
   const base::Closure quit_closure_;
   const scoped_refptr<base::SingleThreadTaskRunner> quit_task_runner_;
 

content/public/common/service_info.h

@@ -9,7 +9,9 @@
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
+#include "base/message_loop/message_loop.h"
 #include "base/single_thread_task_runner.h"
+#include "base/threading/platform_thread.h"
 #include "content/common/content_export.h"
 
 namespace service_manager {
@@ -43,6 +45,14 @@ struct CONTENT_EXPORT ServiceInfo {
   //
   // If |task_runner| is not null, this value is ignored.
   bool use_own_thread = false;
+
+  // If the service uses its own thread, this determines the type of the message
+  // loop used by the thread.
+  base::MessageLoop::Type message_loop_type = base::MessageLoop::TYPE_DEFAULT;
+
+  // If the service uses its own thread, this determines the priority of the
+  // thread.
+  base::ThreadPriority thread_priority = base::ThreadPriority::NORMAL;
 };
 
 }  // namespace content