Apply sanity check for accelerated rendering unconditionally.

third_party/WebKit/Source/modules/vr/VRDisplay.cpp

 // 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 "modules/vr/VRDisplay.h"
 
 #include "core/css/StylePropertySet.h"
 #include "core/dom/DOMException.h"
 #include "core/dom/DocumentUserGestureToken.h"
 #include "core/dom/FrameRequestCallback.h"
@@ skipping 540 matching lines @@
       if (!m_submit_frame_client_binding.WaitForIncomingMethodCall()) {
         DLOG(ERROR) << "Failed to receive SubmitFrame response";
         break;
       }
     }
   }
 
   RefPtr<Image> imageRef = m_renderingContext->getImage(
       PreferAcceleration, SnapshotReasonCreateImageBitmap);
 
-  // Hardware-accelerated rendering should always be texture backed.
-  // I hope nobody is trying to do WebVR with software rendering.
-  DCHECK(imageRef->isTextureBacked());
+  // Hardware-accelerated rendering should always be texture backed,
+  // as implemented by AcceleratedStaticBitmapImage. Ensure this is
+  // the case, don't attempt to render if using an unexpected drawing
+  // path.
+  if (!imageRef->isTextureBacked()) {
+    NOTREACHED() << "WebVR requires hardware-accelerated rendering to texture";
+    return;
+  }
 
   // The AcceleratedStaticBitmapImage must be kept alive until the
   // mailbox is used via createAndConsumeTextureCHROMIUM, the mailbox
   // itself does not keep it alive. We must keep a reference to the
   // image until the mailbox was consumed.
   StaticBitmapImage* staticImage =
       static_cast<StaticBitmapImage*>(imageRef.get());
   staticImage->ensureMailbox();
 
   if (waitForPreviousTransferToFinish) {
@@ skipping 204 matching lines @@
   visitor->trace(m_stageParameters);
   visitor->trace(m_eyeParametersLeft);
   visitor->trace(m_eyeParametersRight);
   visitor->trace(m_layer);
   visitor->trace(m_renderingContext);
   visitor->trace(m_scriptedAnimationController);
   visitor->trace(m_pendingPresentResolvers);
 }
 
 }  // namespace blink