Add tiled rendering as an option to GM.

Use an SkGPipe to play back drawing into tiles.
This will help us to debug differences in drawing
while tiled.

Pass --tiledPipe to gm to use the tiled pipe.
Review URL: https://codereview.appspot.com/6295050

git-svn-id: http://skia.googlecode.com/svn/trunk@4199 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gyp/gm.gyp b/gyp/gm.gyp
index 980c199..c3f359c 100644
--- a/gyp/gm.gyp
+++ b/gyp/gm.gyp
@@ -17,6 +17,8 @@
         '../gm/gm.cpp',
         '../gm/gmmain.cpp',
         '../gm/system_preferences_default.cpp',
+        '../src/pipe/utils/SamplePipeControllers.h',
+        '../src/pipe/utils/SamplePipeControllers.cpp',
       ],
       'dependencies': [
         'core.gyp:core',