Fixes WebVR presentation from within VRShell.

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 a9f3bff1aa4e5845726f4dd48dfc6e0435aa36ae..47f42b2716d664366b2ffffae6ceb56882eee167 100644
--- a/chrome/browser/android/vr_shell/vr_shell.cc
+++ b/chrome/browser/android/vr_shell/vr_shell.cc
@@ -371,6 +371,13 @@ void VrShell::CreateVRDisplayInfo(
                                      device_id));
 }
 
+void VrShell::SetSubmitClient(
+    device::mojom::VRSubmitFrameClientPtr submit_client) {
+  PostToGlThreadWhenReady(
+      base::Bind(&VrShellGl::SetSubmitClient, gl_thread_->GetVrShellGl(),
+                 base::Passed(submit_client.PassInterface())));
+}
+
 base::android::ScopedJavaGlobalRef<jobject> VrShell::TakeContentSurface(
     JNIEnv* env,
     const JavaParamRef<jobject>& obj) {
@@ -405,10 +412,6 @@ void VrShell::ContentSurfaceChanged(jobject surface) {
 }
 
 void VrShell::GvrDelegateReady() {
-  PostToGlThreadWhenReady(base::Bind(
-      &VrShellGl::SetSubmitClient, gl_thread_->GetVrShellGl(),
-      base::Passed(
-          delegate_provider_->TakeSubmitFrameClient().PassInterface())));
   delegate_provider_->SetPresentingDelegate(this, gvr_api_);

[tiborg, 2017/03/24 21:58:51]

It would be helpful if this call was made in the constructor of VrShell. By
doing so, the presenting delegate in VrShellDelegate would be already set by the
time SetPresentResult is called. However, moving this to the constructor breaks
entering VRShell from 2D pages. The rendering does not start. Is there a way to
make this work?

[mthiesse, 2017/03/30 15:29:46]

What do you mean by the rendering doesn't start? How are you even moving this to
the constructor, when you don't have a submit client when not presenting?

[tiborg, 2017/03/30 22:19:57]

It goes into the binocular view but it does not render any elements. This call
doesn't need a submit client. The submit client is passed once a present request
is successful. Is was just wondering if there is an easy way to do it. If not I
would just leave it for now.

 }