Implement lazy initialization for VrShellDelegate

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 <utility>
 
 #include "base/android/jni_android.h"
 #include "chrome/browser/android/vr_shell/non_presenting_gvr_delegate.h"
 #include "device/vr/android/gvr/gvr_device.h"
 #include "device/vr/android/gvr/gvr_device_provider.h"
 #include "device/vr/android/gvr/gvr_gamepad_data_fetcher.h"
 #include "jni/VrShellDelegate_jni.h"
 
 using base::android::JavaParamRef;
 using base::android::AttachCurrentThread;
 
 namespace vr_shell {
 
 VrShellDelegate::VrShellDelegate(JNIEnv* env, jobject obj)
     : weak_ptr_factory_(this) {
   j_vr_shell_delegate_.Reset(env, obj);
-  GvrDelegateProvider::SetInstance(this);
 }
 
 VrShellDelegate::~VrShellDelegate() {
-  GvrDelegateProvider::SetInstance(nullptr);
   if (device_provider_) {
     device_provider_->Device()->OnDelegateChanged();
   }
 }
 
+device::GvrDelegateProvider* VrShellDelegate::CreateVrShellDelegate() {
+  JNIEnv* env = AttachCurrentThread();
+  base::android::ScopedJavaLocalRef<jobject> jdelegate =
+      Java_VrShellDelegate_getInstance(env);
+  if (!jdelegate.is_null())
+    return GetNativeVrShellDelegate(env, jdelegate.obj());
+  return nullptr;
+}
+
 VrShellDelegate* VrShellDelegate::GetNativeVrShellDelegate(JNIEnv* env,
                                                            jobject jdelegate) {
   return reinterpret_cast<VrShellDelegate*>(
       Java_VrShellDelegate_getNativePointer(env, jdelegate));
 }
 
 void VrShellDelegate::SetDelegate(device::GvrDelegate* delegate,
                                   gvr_context* context) {
   context_ = context;
   delegate_ = delegate;
@@ skipping 64 matching lines @@
     non_presenting_delegate_->Pause();
   }
 }
 
 void VrShellDelegate::OnResume(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   if (non_presenting_delegate_) {
     non_presenting_delegate_->Resume();
   }
 }
 
+void VrShellDelegate::Destroy(JNIEnv* env, const JavaParamRef<jobject>& obj) {
+  delete this;
+}
+
 void VrShellDelegate::ShowTab(int id) {
   JNIEnv* env = AttachCurrentThread();
   Java_VrShellDelegate_showTab(env, j_vr_shell_delegate_.obj(), id);
 }
 
 void VrShellDelegate::SetDeviceProvider(
     device::GvrDeviceProvider* device_provider) {
   CHECK(!device_provider_);
   device_provider_ = device_provider;
   if (!delegate_)
     CreateNonPresentingDelegate();
   device_provider_->Device()->OnDelegateChanged();
 }
 
 void VrShellDelegate::ClearDeviceProvider() {
   non_presenting_delegate_ = nullptr;
   JNIEnv* env = AttachCurrentThread();
   Java_VrShellDelegate_shutdownNonPresentingNativeContext(
       env, j_vr_shell_delegate_.obj());
-  device_provider_->Device()->OnDelegateChanged();
   device_provider_ = nullptr;
 }
 
 void VrShellDelegate::RequestWebVRPresent(
     const base::Callback<void(bool)>& callback) {
   if (!present_callback_.is_null()) {
     // Can only handle one request at a time. This is also extremely unlikely to
     // happen in practice.
     callback.Run(false);
     return;
@@ skipping 53 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));
 }
 
+static void OnLibraryAvailable(JNIEnv* env, const JavaParamRef<jclass>& clazz) {
+  device::GvrDelegateProvider::SetInstance(
+      base::Bind(&VrShellDelegate::CreateVrShellDelegate));
+}
+
 }  // namespace vr_shell