Apply sanity check for accelerated rendering unconditionally.

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

Index: third_party/WebKit/Source/modules/vr/VRDisplay.cpp
diff --git a/third_party/WebKit/Source/modules/vr/VRDisplay.cpp b/third_party/WebKit/Source/modules/vr/VRDisplay.cpp
index 0c85c13a84877f6bde86a1ac2583841d2cf1ddd4..a6486fd050a9fc13e9c8b7840da6866a22b9947e 100644
--- a/third_party/WebKit/Source/modules/vr/VRDisplay.cpp
+++ b/third_party/WebKit/Source/modules/vr/VRDisplay.cpp
@@ -558,9 +558,15 @@ void VRDisplay::submitFrame() {
   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 software rendering. We
+  // could implement an alternate slow path here for tests if

[ddorwin, 2017/03/13 20:05:38]

How/when will we know?

[klausw, 2017/03/13 20:20:26]

Symptom would be the eye views staying black with no rendered content while
presenting. AFAIK it's usual to keep sanity check errors to DLOG to avoid
excessive strings being added. This path shouldn't get hit on any real hardware
as far as I know, not sure if it would get activated on emulators or if running
with "use hardware acceleration when available" disabled or equivalent. I didn't
see a way to turn that off on my Android device to confirm.

+  // applicable.
+  if (!imageRef->isTextureBacked()) {
+    DLOG(ERROR) << "WebVR requires hardware-accelerated rendering to texture";
+    return;
+  }
 
   // The AcceleratedStaticBitmapImage must be kept alive until the
   // mailbox is used via createAndConsumeTextureCHROMIUM, the mailbox