content: Improve thread priority for raster threads.

content/renderer/raster_worker_pool.h

Index: content/renderer/raster_worker_pool.h
diff --git a/content/renderer/raster_worker_pool.h b/content/renderer/raster_worker_pool.h
index dfa325c24c7ccf410c569b397870e9fbdf3b295e..b4ddf9a61c251e6f759400ccff94266941a2f604 100644
--- a/content/renderer/raster_worker_pool.h
+++ b/content/renderer/raster_worker_pool.h
@@ -55,8 +55,7 @@ class CONTENT_EXPORT RasterWorkerPool : public base::TaskRunner,
 
   // Spawn |num_threads| number of threads and start running work on the
   // worker threads.
-  void Start(int num_threads,
-             const base::SimpleThread::Options& thread_options);
+  void Start(int num_threads);
 
   // Finish running all the posted tasks (and nested task posted by those tasks)
   // of all the associated task runners.