Remove options to disable deadline scheduling

cc/scheduler/scheduler_state_machine.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/scheduler/scheduler_state_machine.h"
 
 #include "base/debug/trace_event.h"
 #include "base/format_macros.h"
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
@@ skipping 458 matching lines @@
 
   // We do not need commits if we are not visible, unless there's a
   // request for a readback.
   if (!visible_)
     return false;
 
   // We want to start the first commit after we get a new output surface ASAP.
   if (output_surface_state_ == OUTPUT_SURFACE_WAITING_FOR_FIRST_COMMIT)
     return true;
 
-  // With deadline scheduling enabled, we should not send BeginMainFrame while
-  // we are in BEGIN_IMPL_FRAME_STATE_IDLE, since we might have new user input
-  // coming in soon.
-  // However, if we are not expecting a BeginImplFrame to take us out of idle,
-  // we should not early out here to avoid blocking commits forever.
-  // This only works well when deadline scheduling is enabled because there is
-  // an interval over which to accept the commit and draw. Without deadline
-  // scheduling, delaying the commit could prevent us from having something
-  // to draw on the next BeginImplFrame.
+  // We should not send BeginMainFrame while we are in
+  // BEGIN_IMPL_FRAME_STATE_IDLE since we might have new
+  // user input arriving soon.
   // TODO(brianderson): Allow sending BeginMainFrame while idle when the main
   // thread isn't consuming user input.
-  if (settings_.deadline_scheduling_enabled &&
-      begin_impl_frame_state_ == BEGIN_IMPL_FRAME_STATE_IDLE &&
+  if (begin_impl_frame_state_ == BEGIN_IMPL_FRAME_STATE_IDLE &&
       BeginImplFrameNeeded())
     return false;
 
   // We need a new commit for the forced redraw. This honors the
   // single commit per interval because the result will be swapped to screen.
   if (forced_redraw_state_ == FORCED_REDRAW_STATE_WAITING_FOR_COMMIT)
     return true;
 
   // After this point, we only start a commit once per frame.
   if (HasSentBeginMainFrameThisFrame())
@@ skipping 655 matching lines @@
     case OUTPUT_SURFACE_ACTIVE:
     case OUTPUT_SURFACE_WAITING_FOR_FIRST_COMMIT:
     case OUTPUT_SURFACE_WAITING_FOR_FIRST_ACTIVATION:
       return true;
   }
   NOTREACHED();
   return false;
 }
 
 }  // namespace cc