[CRD iOS] Some fixes for rendering

remoting/ios/app/host_view_controller.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.
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 #import "remoting/ios/app/host_view_controller.h"
 
@@ skipping 57 matching lines @@
   return YES;
 }
 
 - (void)viewDidAppear:(BOOL)animated {
   [super viewDidAppear:animated];
   GLKView* glView = (GLKView*)self.view;
   glView.context = [_client.displayHandler GetEAGLContext];
   [_client.displayHandler onSurfaceCreated:glView];
 
   // viewDidLayoutSubviews may be called before viewDidAppear, in which case
-  // the surface is not ready and onSurfaceChanged will be no-op.
+  // the surface is not ready to handle the transformation matrix.
   // Call onSurfaceChanged here to cover that case.
   [_client surfaceChanged:self.view.frame];
 }
 
+- (void)viewDidDisappear:(BOOL)animated {
+  [super viewDidDisappear:animated];
+  [(GLKView*)self.view deleteDrawable];
+}
+
 - (void)viewWillAppear:(BOOL)animated {
   [super viewWillAppear:animated];
 
   _clientGestures =
       [[ClientGestures alloc] initWithView:self.view client:_client];
 }
 
 - (void)viewWillDisappear:(BOOL)animated {
   [super viewWillDisappear:animated];
 
   _clientGestures = nil;
 }
 
 - (void)viewDidLayoutSubviews {
   [super viewDidLayoutSubviews];
 
-  [_client surfaceChanged:self.view.frame];
+  if (((GLKView*)self.view).context != nil) {
+    // If the context is not set yet, the view size will be set in
+    // viewDidAppear.
+    [_client surfaceChanged:self.view.bounds];
+  }
 
   CGSize btnSize = _floatingButton.frame.size;
   _floatingButton.frame =
       CGRectMake(self.view.frame.size.width - btnSize.width - kFabInset,
                  self.view.frame.size.height - btnSize.height - kFabInset,
                  btnSize.width, btnSize.height);
 }
 
 #pragma mark - Private
 
 - (void)didTap:(id)sender {
   // TODO(nicholss): The FAB is being used to close the window at the moment
   // just as a demo  as the integration continues. This will not be the case
   // in the final app.
   [_client disconnectFromHost];
   [self dismissViewControllerAnimated:YES completion:nil];
 }
 
 @end