cc: Move draw params from SetExternalDrawConstraints to OnDraw

cc/test/layer_tree_pixel_test.cc

Index: cc/test/layer_tree_pixel_test.cc
diff --git a/cc/test/layer_tree_pixel_test.cc b/cc/test/layer_tree_pixel_test.cc
index f29ae8669f657a8b1e367388227132fc5173dec2..77e946ab582c06d1a3168a6a09e3e98ab86573c8 100644
--- a/cc/test/layer_tree_pixel_test.cc
+++ b/cc/test/layer_tree_pixel_test.cc
@@ -74,14 +74,7 @@ void LayerTreePixelTest::WillCommitCompleteOnThread(LayerTreeHostImpl* impl) {
   EXPECT_EQ(gfx::Point().ToString(), viewport.origin().ToString());
   // Be that influence!
   viewport += gfx::Vector2d(20, 10);
-  bool resourceless_software_draw = false;
-  gfx::Transform identity = gfx::Transform();
-  impl->SetExternalDrawConstraints(identity,
-                                   viewport,
-                                   viewport,
-                                   viewport,
-                                   identity,
-                                   resourceless_software_draw);
+  impl->SetExternalViewportForTesting(viewport);
   EXPECT_EQ(viewport.ToString(), impl->DeviceViewport().ToString());
 }