PROTOTYPE (incomplete): Add quad renderer and stub bits to handle security warnings.

chrome/browser/android/vr_shell/vr_shell_gl.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/vr_shell_gl.h"
 
 #include <chrono>
 #include <limits>
 #include <utility>
 
@@ skipping 975 matching lines @@
     }
   }
 }
 
 void VrShellGl::DrawElements(const vr::Mat4f& view_proj_matrix,
                              const std::vector<const UiElement*>& elements) {
   for (const auto* rect : elements) {
     vr::Mat4f transform;
     vr::MatrixMul(view_proj_matrix, rect->TransformMatrix(), &transform);
 
+    if (rect->Render(vr_shell_renderer_.get())) {
+      continue;
+    }
     switch (rect->fill) {
-      case Fill::SKIA: {
-        break;
-      }
       case Fill::OPAQUE_GRADIENT: {
-        vr_shell_renderer_->GetTexturedQuadRenderer()->Flush();
         vr_shell_renderer_->GetGradientQuadRenderer()->Draw(
             transform, rect->edge_color, rect->center_color,
             rect->computed_opacity);
+        vr_shell_renderer_->GetTexturedQuadRenderer()->Flush();

[cjgrant, 2017/04/19 16:24:52]

This may not be great, but I think this Flush optimization is not adding
anything right now.

         break;
       }
       case Fill::GRID_GRADIENT: {
-        vr_shell_renderer_->GetTexturedQuadRenderer()->Flush();
         vr_shell_renderer_->GetGradientGridRenderer()->Draw(
             transform, rect->edge_color, rect->center_color,
             rect->gridline_count, rect->computed_opacity);
+        vr_shell_renderer_->GetTexturedQuadRenderer()->Flush();
         break;
       }
       case Fill::CONTENT: {
         gfx::RectF copy_rect(0, 0, 1, 1);
         vr_shell_renderer_->GetTexturedQuadRenderer()->AddQuad(
             content_texture_id_, transform, copy_rect, rect->computed_opacity);
+        vr_shell_renderer_->GetTexturedQuadRenderer()->Flush();
         break;
       }
       default:
         break;
     }
   }
-
-  vr_shell_renderer_->GetTexturedQuadRenderer()->Flush();
 }
 
 std::vector<const UiElement*> VrShellGl::GetElementsInDrawOrder(
     const vr::Mat4f& view_matrix,
     const std::vector<const UiElement*>& elements) {
   typedef std::pair<float, const UiElement*> DistanceElementPair;
   std::vector<DistanceElementPair> zOrderedElementPairs;
   zOrderedElementPairs.reserve(elements.size());
 
   for (const auto* element : elements) {
@@ skipping 289 matching lines @@
   // InitializeGl. Revisit if the initialization order changes.
   device::mojom::VRDisplayInfoPtr info =
       device::GvrDelegate::CreateVRDisplayInfo(gvr_api_.get(),
                                                webvr_surface_size_, device_id);
   main_thread_task_runner_->PostTask(
       FROM_HERE,
       base::Bind(&RunVRDisplayInfoCallback, callback, base::Passed(&info)));
 }
 
 }  // namespace vr_shell