[CRD iOS] Some fixes for rendering

remoting/client/jni/jni_gl_display_handler.cc

 // Copyright 2016 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/client/jni/jni_gl_display_handler.h"
 
 #include <android/native_window_jni.h>
 #include <array>
 
 #include "base/android/jni_android.h"
@@ skipping 141 matching lines @@
   renderer_->OnSurfaceCreated(base::MakeUnique<GlCanvas>(
       static_cast<int>(egl_context_->client_version())));
 
   runtime_->network_task_runner()->PostTask(
       FROM_HERE, base::Bind(&DualBufferFrameConsumer::RequestFullDesktopFrame,
                             frame_consumer_));
 }
 
 void JniGlDisplayHandler::Core::SurfaceChanged(int width, int height) {
   DCHECK(runtime_->display_task_runner()->BelongsToCurrentThread());
+  // Note that this doesn't resize the OpenGL viewport. The OpenGL viewport is
+  // initialized once it is first bound to the surface. We don't need to call
+  // glViewport() since the activity/surface is recreated and hence the viewport
+  // is re-initialized every time the surface size is changed.
   renderer_->OnSurfaceChanged(width, height);
 }
 
 void JniGlDisplayHandler::Core::SurfaceDestroyed() {
   DCHECK(runtime_->display_task_runner()->BelongsToCurrentThread());
   DCHECK(egl_context_);
   DCHECK(window_);
   renderer_->OnSurfaceDestroyed();
   egl_context_.reset();
   ANativeWindow_release(window_);
@@ skipping 150 matching lines @@
                                 java_display_);
 }
 
 void JniGlDisplayHandler::OnCanvasSizeChanged(int width, int height) {
   DCHECK(runtime_->ui_task_runner()->BelongsToCurrentThread());
   Java_GlDisplay_changeCanvasSize(base::android::AttachCurrentThread(),
                                   java_display_, width, height);
 }
 
 }  // namespace remoting