WebVR: avoid race conditions for partially-initialized display

chrome/browser/android/vr_shell/vr_shell_delegate.cc

Index: chrome/browser/android/vr_shell/vr_shell_delegate.cc
diff --git a/chrome/browser/android/vr_shell/vr_shell_delegate.cc b/chrome/browser/android/vr_shell/vr_shell_delegate.cc
index d7779a200728ea51394eecb97c42a29e7a1a134a..a5077eb12af779e0fd6593f699a356ea4a46d035 100644
--- a/chrome/browser/android/vr_shell/vr_shell_delegate.cc
+++ b/chrome/browser/android/vr_shell/vr_shell_delegate.cc
@@ -33,7 +33,7 @@ class GvrNonPresentingDelegate : public device::GvrDelegate {
                           uint32_t pose_index) override {}
   void SetWebVRRenderSurfaceSize(int width, int height) override {}
   gvr::Sizei GetWebVRCompositorSurfaceSize() override {
-    return device::kFallbackRenderTargetSize; }
+    return device::kInvalidRenderTargetSize; }
   gvr::GvrApi* gvr_api() override { return gvr_api_.get(); }
   base::WeakPtr<GvrNonPresentingDelegate> GetWeakPtr() {
     return weak_ptr_factory_.GetWeakPtr();