content: Add an overridable task runner to ChildThreadImpl

content/child/child_thread_impl.cc

Index: content/child/child_thread_impl.cc
diff --git a/content/child/child_thread_impl.cc b/content/child/child_thread_impl.cc
index b6a2eea2b8aa2e4fde1c6d6a0c41023ba0bb5576..9bb754e46e6dc09e1ae0125eebbe54987c224cda 100644
--- a/content/child/child_thread_impl.cc
+++ b/content/child/child_thread_impl.cc
@@ -207,7 +207,8 @@ ChildThreadImpl::Options::Options()
     : channel_name(base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
           switches::kProcessChannelID)),
       use_mojo_channel(false),
-      in_browser_process(false) {
+      in_browser_process(false),
+      task_runner(base::MessageLoopProxy::current()) {
 }
 
 ChildThreadImpl::Options::~Options() {
@@ -242,6 +243,13 @@ ChildThreadImpl::Options::Builder::AddStartupFilter(
   return *this;
 }
 
+ChildThreadImpl::Options::Builder&
+ChildThreadImpl::Options::Builder::WithTaskRunner(
+    scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
+  options_.task_runner = task_runner;
+  return *this;
+}
+
 ChildThreadImpl::Options ChildThreadImpl::Options::Builder::Build() {
   return options_;
 }
@@ -255,14 +263,12 @@ bool ChildThreadImpl::ChildThreadMessageRouter::Send(IPC::Message* msg) {
 }
 
 ChildThreadImpl::ChildThreadImpl()
-    : router_(this),
-      in_browser_process_(false),
-      channel_connected_factory_(this) {
-  Init(Options::Builder().Build());
+    : ChildThreadImpl(Options::Builder().Build()) {
 }
 
 ChildThreadImpl::ChildThreadImpl(const Options& options)
     : router_(this),
+      task_runner_(options.task_runner),
       in_browser_process_(options.in_browser_process),
       channel_connected_factory_(this) {
   Init(options);
@@ -308,8 +314,7 @@ void ChildThreadImpl::Init(const Options& options) {
   thread_safe_sender_ = new ThreadSafeSender(
       base::MessageLoopProxy::current().get(), sync_message_filter_.get());
 
-  resource_dispatcher_.reset(new ResourceDispatcher(
-      this, message_loop()->task_runner()));
+  resource_dispatcher_.reset(new ResourceDispatcher(this, GetTaskRunner()));
   websocket_dispatcher_.reset(new WebSocketDispatcher);
   file_system_dispatcher_.reset(new FileSystemDispatcher());
 
@@ -474,6 +479,10 @@ bool ChildThreadImpl::Send(IPC::Message* msg) {
   return channel_->Send(msg);
 }
 
+scoped_refptr<base::SingleThreadTaskRunner> ChildThreadImpl::GetTaskRunner() {
+  return task_runner_;
+}
+
 #if defined(OS_WIN)
 void ChildThreadImpl::PreCacheFont(const LOGFONT& log_font) {
   Send(new ChildProcessHostMsg_PreCacheFont(log_font));