cc: Remove Display::SetExternalViewport.

cc/surfaces/display.cc

Index: cc/surfaces/display.cc
diff --git a/cc/surfaces/display.cc b/cc/surfaces/display.cc
index 8309f0b19cb9d3b00156763e00f82de91d985e21..88dbfff568eb56ba80b1da53dbb07de1a6b3bbf4 100644
--- a/cc/surfaces/display.cc
+++ b/cc/surfaces/display.cc
@@ -150,10 +150,6 @@ void Display::SetExternalClip(const gfx::Rect& clip) {
   external_clip_ = clip;
 }
 
-void Display::SetExternalViewport(const gfx::Rect& viewport) {
-  external_viewport_ = viewport;
-}
-
 void Display::SetOutputIsSecure(bool secure) {
   if (secure == output_is_secure_)
     return;
@@ -297,9 +293,7 @@ bool Display::DrawAndSwap() {
   client_->DisplayWillDrawAndSwap(should_draw, frame_data->render_pass_list);
 
   if (should_draw) {
-    gfx::Rect device_viewport_rect = external_viewport_.IsEmpty()
-                                         ? gfx::Rect(current_surface_size_)
-                                         : external_viewport_;
+    gfx::Rect device_viewport_rect(current_surface_size_);
     gfx::Rect device_clip_rect =
         external_clip_.IsEmpty() ? device_viewport_rect : external_clip_;