Replaced is_null() with is_valid in SurfaceId and related classes.

services/ui/ws/server_window_compositor_frame_sink.cc

 // Copyright 2015 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 "services/ui/ws/server_window_compositor_frame_sink.h"
 
 #include "base/callback.h"
 #include "base/message_loop/message_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
@@ skipping 51 matching lines @@
     bool needs_begin_frame) {
   needs_begin_frame_ = needs_begin_frame;
   UpdateNeedsBeginFramesInternal();
 }
 
 void ServerWindowCompositorFrameSink::SubmitCompositorFrame(
     cc::CompositorFrame frame) {
   gfx::Size frame_size = frame.render_pass_list[0]->output_rect.size();
   // If the size of the CompostiorFrame has changed then destroy the existing
   // Surface and create a new one of the appropriate size.
-  if (local_frame_id_.is_null() || frame_size != last_submitted_frame_size_) {
-    if (!local_frame_id_.is_null())
+  if (!local_frame_id_.is_valid() || frame_size != last_submitted_frame_size_) {
+    if (local_frame_id_.is_valid())
       surface_factory_.Destroy(local_frame_id_);
     local_frame_id_ = surface_id_allocator_.GenerateId();
     surface_factory_.Create(local_frame_id_);
     if (display_)
       display_->Resize(frame_size);
   }
   ++ack_pending_count_;
   surface_factory_.SubmitCompositorFrame(
       local_frame_id_, std::move(frame),
       base::Bind(&ServerWindowCompositorFrameSink::DidReceiveCompositorFrameAck,
@@ skipping 131 matching lines @@
 
   added_frame_observer_ = needs_begin_frame_;
   if (needs_begin_frame_)
     begin_frame_source_->AddObserver(this);
   else
     begin_frame_source_->RemoveObserver(this);
 }
 
 }  // namespace ws
 }  // namespace ui