WebVR: avoid race conditions for partially-initialized display

chrome/browser/android/vr_shell/vr_shell.cc

Index: chrome/browser/android/vr_shell/vr_shell.cc
diff --git a/chrome/browser/android/vr_shell/vr_shell.cc b/chrome/browser/android/vr_shell/vr_shell.cc
index a649757d1fa4bf7b6a466cbc35e1883bab7bf3bf..90456fd60192c92960f1e2210719bb461e36cc6a 100644
--- a/chrome/browser/android/vr_shell/vr_shell.cc
+++ b/chrome/browser/android/vr_shell/vr_shell.cc
@@ -569,6 +569,10 @@ void VrShell::DrawFrame(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   if (html_interface_->GetMode() == UiInterface::Mode::WEB_VR) {
     // If needed, resize the primary buffer for use with WebVR.
     if (render_size_primary_ != render_size_primary_webvr_) {
+      if (!render_size_primary_webvr_.width) {
+        VLOG(2) << "WebVR rendering size not known yet, dropping frame";
+        return;
+      }
       render_size_primary_ = render_size_primary_webvr_;
       swap_chain_->ResizeBuffer(kFramePrimaryBuffer, render_size_primary_);
     }