Fix double-deletion of VR Shell when exiting webVR in onPause.

chrome/browser/android/vr_shell/vr_shell_delegate.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_delegate.h"
 
 #include "base/android/jni_android.h"
 #include "chrome/browser/android/vr_shell/vr_shell.h"
 #include "device/vr/android/gvr/gvr_device_provider.h"
 #include "jni/VrShellDelegate_jni.h"
@@ skipping 45 matching lines @@
 VrShellDelegate* VrShellDelegate::GetNativeDelegate(
     JNIEnv* env, jobject jdelegate) {
   long native_delegate = Java_VrShellDelegate_getNativePointer(env, jdelegate);
   return reinterpret_cast<VrShellDelegate*>(native_delegate);
 }
 
 base::WeakPtr<device::GvrDeviceProvider> VrShellDelegate::GetDeviceProvider() {
   return device_provider_;
 }
 
-void VrShellDelegate::ExitWebVRIfNecessary(JNIEnv* env, jobject obj) {
-  if (!device_provider_)
-    return;
-
-  device_provider_->OnGvrDelegateRemoved();
-}
-
 bool VrShellDelegate::RequestWebVRPresent(
     base::WeakPtr<device::GvrDeviceProvider> device_provider) {
   // Only set one device provider at a time
   DCHECK(!device_provider_);
   device_provider_ = device_provider;
 
   // If/When VRShell is ready for use it will call OnVrShellReady.
   JNIEnv* env = AttachCurrentThread();
   Java_VrShellDelegate_enterVRIfNecessary(env, j_vr_shell_delegate_.obj(),
                                           true);
@@ skipping 38 matching lines @@
 
 bool RegisterVrShellDelegate(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 jlong Init(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   return reinterpret_cast<intptr_t>(new VrShellDelegate(env, obj));
 }
 
 }  // namespace vr_shell