Adding ThreadChecker validation to d'tors for client classes

remoting/ios/display/gl_demo_screen.mm

 // Copyright 2017 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 "remoting/ios/display/gl_demo_screen.h"
 
 #include "base/logging.h"
 #include "remoting/client/display/canvas.h"
 #include "remoting/client/display/gl_math.h"
 
@@ skipping 17 matching lines @@
     "}";
 
 const GLchar* a_position = "a_position";
 
 }  // namespace
 
 // This is a demo screen that can be added to the renderer to test the drawable
 // integration. This will draw an expanding checkerboard pattern to the screen.
 GlDemoScreen::GlDemoScreen() : weak_factory_(this)  {}
 
-GlDemoScreen::~GlDemoScreen() {}
+GlDemoScreen::~GlDemoScreen() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+}
 
 void GlDemoScreen::SetCanvas(base::WeakPtr<Canvas> canvas) {
   canvas_ = canvas;
 
   // Create and compile vertex shader.
   GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
   glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
   glCompileShader(vertexShader);
 
   // Create and compile fragment shader.
@@ skipping 57 matching lines @@
   }
   return false;
 }
 
 base::WeakPtr<Drawable> GlDemoScreen::GetWeakPtr() {
   DCHECK(thread_checker_.CalledOnValidThread());
   return weak_factory_.GetWeakPtr();
 }
 
 }  // namespace remoting