Use PostTaskAndReplyWithResult in plugin_service_impl.cc.

content/browser/plugin_service_impl.h

Index: content/browser/plugin_service_impl.h
diff --git a/content/browser/plugin_service_impl.h b/content/browser/plugin_service_impl.h
index 9e7a5ef1d9bd399752d616730e00444dd1ce48ac..85b64dad4b90782537b745a40a364af5cf17df59 100644
--- a/content/browser/plugin_service_impl.h
+++ b/content/browser/plugin_service_impl.h
@@ -15,8 +15,6 @@
 #endif
 
 #include <map>
-#include <memory>
-#include <set>
 #include <vector>
 
 #include "base/compiler_specific.h"
@@ -43,10 +41,6 @@
 #include "base/files/file_path_watcher.h"
 #endif
 
-namespace base {
-class SingleThreadTaskRunner;
-}
-
 namespace content {
 class BrowserContext;
 class PluginServiceFilter;
@@ -80,7 +74,7 @@ class CONTENT_EXPORT PluginServiceImpl
                            WebPluginInfo* info) override;
   base::string16 GetPluginDisplayNameByPath(
       const base::FilePath& path) override;
-  void GetPlugins(const GetPluginsCallback& callback) override;
+  void GetPlugins(GetPluginsCallback callback) override;
   PepperPluginInfo* GetRegisteredPpapiPluginInfo(
       const base::FilePath& plugin_path) override;
   void SetFilter(PluginServiceFilter* filter) override;
@@ -142,9 +136,8 @@ class CONTENT_EXPORT PluginServiceImpl
 
   void RegisterPepperPlugins();
 
-  // Run on the blocking pool to load the plugins synchronously.
-  void GetPluginsInternal(base::SingleThreadTaskRunner* target_task_runner,
-                          const GetPluginsCallback& callback);
+  // Loads the plugins synchronously in a thread pool.
+  std::vector<WebPluginInfo> GetPluginsInternal();
 
   std::vector<PepperPluginInfo> ppapi_plugins_;