WebVR: avoid race conditions for partially-initialized display

device/vr/android/gvr/gvr_delegate.h

 // 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.
 
 #ifndef DEVICE_VR_ANDROID_GVR_DELEGATE_H
 #define DEVICE_VR_ANDROID_GVR_DELEGATE_H
 
 #include "base/memory/weak_ptr.h"
 #include "device/vr/android/gvr/gvr_device_provider.h"
 #include "device/vr/vr_export.h"
 #include "third_party/gvr-android-sdk/src/ndk/include/vr/gvr/capi/include/gvr_types.h"
 
 namespace gvr {
 class GvrApi;
 }  // namespace gvr
 
 namespace device {
 
-constexpr gvr::Sizei kFallbackRenderTargetSize = {2048, 1024};
+constexpr gvr::Sizei kInvalidRenderTargetSize = {0, 0};
 
 class DEVICE_VR_EXPORT GvrDelegate {
  public:
   virtual void SetWebVRSecureOrigin(bool secure_origin) = 0;
   virtual void SubmitWebVRFrame() = 0;
   virtual void UpdateWebVRTextureBounds(const gvr::Rectf& left_bounds,
                                         const gvr::Rectf& right_bounds) = 0;
 
   virtual void SetGvrPoseForWebVr(const gvr::Mat4f& pose,
                                   uint32_t pose_index) = 0;
@@ skipping 16 matching lines @@
   virtual void DestroyNonPresentingDelegate() = 0;
   virtual void SetListeningForActivate(bool listening) = 0;
 
  private:
   static GvrDelegateProvider* delegate_provider_;
 };
 
 }  // namespace device
 
 #endif  // DEVICE_VR_ANDROID_GVR_DELEGATE_H