WebVR: Add sanity checks for decoded pose index values

device/vr/android/gvr/gvr_device_provider.cc

Index: device/vr/android/gvr/gvr_device_provider.cc
diff --git a/device/vr/android/gvr/gvr_device_provider.cc b/device/vr/android/gvr/gvr_device_provider.cc
index 73cc0fc66e61ec4732877687cc58c288500e6d9a..87fb501a0f2561fc3b331fbb00abeb51fb0c63dd 100644
--- a/device/vr/android/gvr/gvr_device_provider.cc
+++ b/device/vr/android/gvr/gvr_device_provider.cc
@@ -81,6 +81,7 @@ void GvrDeviceProvider::OnGvrDelegateReady(
     const base::WeakPtr<GvrDelegate>& delegate) {
   if (!vr_device_)
     return;
+  VLOG(1) << "Switching to presenting delegate";
   vr_device_->SetDelegate(delegate);
   GamepadDataFetcherManager::GetInstance()->AddFactory(
       new GvrGamepadDataFetcher::Factory(delegate, vr_device_->id()));
@@ -118,6 +119,7 @@ void GvrDeviceProvider::SwitchToNonPresentingDelegate() {
   if (!vr_device_ || !delegate_provider)
     return;
 
+  VLOG(1) << "Switching to non-presenting delegate";
   vr_device_->SetDelegate(delegate_provider->GetNonPresentingDelegate());
 
   // Remove GVR gamepad polling.