content: Rename RasterWorkerPool -> CategorizedWorkerPool.

When this class was implemented, it was used for only raster work. But
we had started using it for other tasks, along with raster tasks, being
scheduled with different interfaces provided in the class.

BUG=599863

Review-Url: https://codereview.chromium.org/2021323002
Cr-Commit-Position: refs/heads/master@{#397079}
diff --git a/content/renderer/render_thread_impl.h b/content/renderer/render_thread_impl.h
index 8e5f140..3fbf1d4 100644
--- a/content/renderer/render_thread_impl.h
+++ b/content/renderer/render_thread_impl.h
@@ -109,7 +109,7 @@
 class P2PSocketDispatcher;
 class PeerConnectionDependencyFactory;
 class PeerConnectionTracker;
-class RasterWorkerPool;
+class CategorizedWorkerPool;
 class RenderThreadObserver;
 class RendererBlinkPlatformImpl;
 class RendererDemuxerAndroid;
@@ -613,7 +613,7 @@
   scoped_refptr<base::SingleThreadTaskRunner> compositor_task_runner_;
 
   // Pool of workers used for raster operations (e.g., tile rasterization).
-  scoped_refptr<RasterWorkerPool> raster_worker_pool_;
+  scoped_refptr<CategorizedWorkerPool> categorized_worker_pool_;
 
   base::CancelableCallback<void(const IPC::Message&)> main_input_callback_;
   scoped_refptr<IPC::MessageFilter> input_event_filter_;