Move the IconLoader to use the task scheduler.

BUG=689520

Review-Url: https://codereview.chromium.org/2953633002
Cr-Commit-Position: refs/heads/master@{#481719}
diff --git a/chrome/browser/icon_loader_chromeos.cc b/chrome/browser/icon_loader_chromeos.cc
index 30f0005..70f78c12 100644
--- a/chrome/browser/icon_loader_chromeos.cc
+++ b/chrome/browser/icon_loader_chromeos.cc
@@ -191,10 +191,11 @@
 }
 
 // static
-content::BrowserThread::ID IconLoader::ReadIconThreadID() {
+scoped_refptr<base::TaskRunner> IconLoader::GetReadIconTaskRunner() {
   // ReadIcon touches non thread safe ResourceBundle images, so it must be on
   // the UI thread.
-  return content::BrowserThread::UI;
+  return content::BrowserThread::GetTaskRunnerForThread(
+      content::BrowserThread::UI);
 }
 
 void IconLoader::ReadIcon() {