Exit VR when our main content tab is hidden (Usually due to links opening in new tab)

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 "base/metrics/histogram_macros.h"
 #include "chrome/browser/android/vr_shell/ui_elements.h"
 #include "chrome/browser/android/vr_shell/ui_interface.h"
 #include "chrome/browser/android/vr_shell/ui_scene.h"
@@ skipping 1096 matching lines @@
   delegate_->ForceExitVr();
 }
 
 void VrShell::ContentWebContentsDestroyed() {
   content_input_manager_.reset();
   main_contents_ = nullptr;
   // TODO(mthiesse): Handle web contents being destroyed.
   delegate_->ForceExitVr();
 }
 
+void VrShell::ContentWasHidden() {
+  // Ensure we don't continue sending input to it.
+  content_input_manager_.reset();
+  // TODO(mthiesse): Handle web contents being hidden.
+  delegate_->ForceExitVr();
+}
+
 void VrShell::SetContentCssSize(float width, float height, float dpr) {
   JNIEnv* env = base::android::AttachCurrentThread();
   Java_VrShellImpl_setContentCssSize(env, j_vr_shell_.obj(), width, height,
                                      dpr);
 }
 
 void VrShell::SetUiCssSize(float width, float height, float dpr) {
   JNIEnv* env = base::android::AttachCurrentThread();
   Java_VrShellImpl_setUiCssSize(env, j_vr_shell_.obj(), width, height, dpr);
 }
@@ skipping 11 matching lines @@
            jboolean for_web_vr) {
   return reinterpret_cast<intptr_t>(new VrShell(
       env, obj, content::WebContents::FromJavaWebContents(content_web_contents),
       reinterpret_cast<ui::WindowAndroid*>(content_window_android),
       content::WebContents::FromJavaWebContents(ui_web_contents),
       reinterpret_cast<ui::WindowAndroid*>(ui_window_android),
       for_web_vr));
 }
 
 }  // namespace vr_shell