VR: Fix invalidation race viewing native pages.

chrome/browser/android/vr_shell/vr_shell.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 "chrome/browser/android/vr_shell/vr_shell.h"
 
 #include <android/native_window_jni.h>
 
 #include <string>
 #include <utility>
@@ skipping 394 matching lines @@
   WaitForGlThread();
   PostToGlThread(
       FROM_HERE,
       base::Bind(&VrShellGl::SetSubmitClient, gl_thread_->GetVrShellGl(),
                  base::Passed(submit_client.PassInterface())));
 }
 
 base::android::ScopedJavaGlobalRef<jobject> VrShell::TakeContentSurface(
     JNIEnv* env,
     const JavaParamRef<jobject>& obj) {
+  if (!content_surface_) {
+    return base::android::ScopedJavaGlobalRef<jobject>(env, nullptr);
+  }
+  taken_surface_ = true;
   compositor_->SurfaceChanged(nullptr);
   base::android::ScopedJavaGlobalRef<jobject> surface(env, content_surface_);
   content_surface_ = nullptr;
   return surface;
 }
 
 void VrShell::RestoreContentSurface(JNIEnv* env,
                                     const JavaParamRef<jobject>& obj) {
+  // Don't try to restore the surface if we haven't successfully taken it yet.
+  if (!taken_surface_)

[ymalik, 2017/05/19 17:23:34]

should we be restoring taken_surface_ to false?

[mthiesse, 2017/05/19 17:59:09]

Oops yes.

+    return;
   WaitForGlThread();
   PostToGlThread(FROM_HERE, base::Bind(&VrShellGl::CreateContentSurface,
                                        gl_thread_->GetVrShellGl()));
 }
 
 void VrShell::SetHistoryButtonsEnabled(JNIEnv* env,
                                        const JavaParamRef<jobject>& obj,
                                        jboolean can_go_back,
                                        jboolean can_go_forward) {
   ui_->SetHistoryButtonsEnabled(can_go_back, can_go_forward);
 }
 
 void VrShell::ContentSurfaceChanged(jobject surface) {
   content_surface_ = surface;
-  compositor_->SurfaceChanged(surface);
   JNIEnv* env = base::android::AttachCurrentThread();
   Java_VrShellImpl_contentSurfaceChanged(env, j_vr_shell_.obj());
+  compositor_->SurfaceChanged(content_surface_);
 }
 
 void VrShell::GvrDelegateReady() {
   delegate_provider_->SetPresentingDelegate(this, gvr_api_);
 }
 
 void VrShell::OnPhysicalBackingSizeChanged(
     JNIEnv* env,
     const JavaParamRef<jobject>& obj,
     const JavaParamRef<jobject>& jweb_contents,
@@ skipping 200 matching lines @@
            jlong gvr_api,
            jboolean reprojected_rendering) {
   return reinterpret_cast<intptr_t>(new VrShell(
       env, obj, reinterpret_cast<ui::WindowAndroid*>(window_android),
       for_web_vr, in_cct,
       VrShellDelegate::GetNativeVrShellDelegate(env, delegate),
       reinterpret_cast<gvr_context*>(gvr_api), reprojected_rendering));
 }
 
 }  // namespace vr_shell