In bench_pictures, use a pool of tiles for multicore drawing.

Also includes some code cleanup and code sharing.

Allow setting the number of threads on the command line.

Rename ThreadSafePipeController::playback to ::draw, to be the same
as SkPicture so DrawTileToCanvas can take a template parameter.

Disallow multithreading with GPU turned on.

Display help information with improper tiled arguments.

BUG=https://code.google.com/p/skia/issues/detail?id=871

Review URL: https://codereview.appspot.com/6536050

git-svn-id: http://skia.googlecode.com/svn/trunk@5602 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/pipe/utils/SamplePipeControllers.h b/src/pipe/utils/SamplePipeControllers.h
index 81b9120..5efd6f0 100644
--- a/src/pipe/utils/SamplePipeControllers.h
+++ b/src/pipe/utils/SamplePipeControllers.h
@@ -64,7 +64,7 @@
      * used the flag SkGPipeWriter::kSimultaneousReaders_Flag, this can be called from different
      * threads simultaneously.
      */
-    void playback(SkCanvas*);
+    void draw(SkCanvas*);
 private:
     enum {
         kMinBlockSize = 4096