Enable gpu rasterization in the vr shell

chrome/browser/android/vr_shell/ui_scene.cc

 // 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 "chrome/browser/android/vr_shell/ui_scene.h"
 
 #include <string>
 #include <utility>
 
 #include "base/memory/ptr_util.h"
@@ skipping 45 matching lines @@
 void UiScene::AddUiElement(std::unique_ptr<UiElement> element) {
   CHECK_GE(element->id(), 0);
   CHECK_EQ(GetUiElementById(element->id()), nullptr);
   if (element->parent_id() >= 0) {
     CHECK_NE(GetUiElementById(element->parent_id()), nullptr);
   } else {
     CHECK_EQ(element->x_anchoring(), XAnchoring::XNONE);
     CHECK_EQ(element->y_anchoring(), YAnchoring::YNONE);
   }
   if (gl_initialized_)
-    element->Initialize();
+    element->Initialize(surface_provider_);
   ui_elements_.push_back(std::move(element));
 }
 
 void UiScene::RemoveUiElement(int element_id) {
   for (auto it = ui_elements_.begin(); it != ui_elements_.end(); ++it) {
     if ((*it)->id() == element_id) {
       if ((*it)->fill() == Fill::CONTENT) {
         content_element_ = nullptr;
       }
       ui_elements_.erase(it);
@@ skipping 135 matching lines @@
                                   parent->opacity());
     element->set_computed_lock_to_fov(parent->lock_to_fov());
   }
 
   vr::MatrixMul(inheritable->to_world, transform->to_world,
                 &transform->to_world);
   element->set_dirty(false);
 }
 
 // TODO(mthiesse): Move this to UiSceneManager.
-void UiScene::OnGLInitialized() {
+void UiScene::OnGLInitialized(VrSurfaceProvider* provider) {
   gl_initialized_ = true;
+  surface_provider_ = provider;
   for (auto& element : ui_elements_) {
-    element->Initialize();
+    element->Initialize(provider);
   }
 }
 
 }  // namespace vr_shell