Implement our own GLThread for VR Shell.

chrome/browser/android/vr_shell/vr_shell_gl.cc

Index: chrome/browser/android/vr_shell/vr_shell_gl.cc
diff --git a/chrome/browser/android/vr_shell/vr_shell.cc b/chrome/browser/android/vr_shell/vr_shell_gl.cc
similarity index 62%
copy from chrome/browser/android/vr_shell/vr_shell.cc
copy to chrome/browser/android/vr_shell/vr_shell_gl.cc
index 8fad473cc54708ffc5cedc0da52b4d5bcb9dd974..a2ac61588d22344527cf9a215cd35587f0e756c6 100644
--- a/chrome/browser/android/vr_shell/vr_shell.cc
+++ b/chrome/browser/android/vr_shell/vr_shell_gl.cc
@@ -2,38 +2,29 @@
 // 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.h"
+#include "chrome/browser/android/vr_shell/vr_shell_gl.h"
 
+#include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "chrome/browser/android/vr_shell/ui_elements.h"
 #include "chrome/browser/android/vr_shell/ui_interface.h"
 #include "chrome/browser/android/vr_shell/ui_scene.h"
-#include "chrome/browser/android/vr_shell/vr_compositor.h"
 #include "chrome/browser/android/vr_shell/vr_controller.h"
 #include "chrome/browser/android/vr_shell/vr_gl_util.h"
 #include "chrome/browser/android/vr_shell/vr_input_manager.h"
-#include "chrome/browser/android/vr_shell/vr_shell_delegate.h"
+#include "chrome/browser/android/vr_shell/vr_math.h"
+#include "chrome/browser/android/vr_shell/vr_shell.h"
 #include "chrome/browser/android/vr_shell/vr_shell_renderer.h"
-#include "chrome/browser/android/vr_shell/vr_usage_monitor.h"
-#include "chrome/browser/android/vr_shell/vr_web_contents_observer.h"
-#include "content/public/browser/navigation_controller.h"
-#include "content/public/browser/render_view_host.h"
-#include "content/public/browser/render_widget_host.h"
-#include "content/public/browser/render_widget_host_view.h"
-#include "content/public/browser/web_contents.h"
-#include "content/public/common/referrer.h"
-#include "device/vr/android/gvr/gvr_device_provider.h"
-#include "jni/VrShellImpl_jni.h"
-#include "ui/android/view_android.h"
-#include "ui/android/window_android.h"
-#include "ui/base/page_transition_types.h"
-#include "ui/display/display.h"
-#include "ui/display/screen.h"
+#include "third_party/WebKit/public/platform/WebInputEvent.h"
+#include "ui/gfx/vsync_provider.h"
+#include "ui/gl/android/scoped_java_surface.h"
+#include "ui/gl/android/surface_texture.h"
 #include "ui/gl/gl_bindings.h"
+#include "ui/gl/gl_context.h"
+#include "ui/gl/gl_surface.h"
 #include "ui/gl/init/gl_factory.h"
 
-using base::android::JavaParamRef;
-
 namespace vr_shell {
 
 namespace {
@@ -95,10 +86,6 @@ static constexpr int kViewportListHeadlockedOffset = 2;
 // data. Must match the magic numbers used in blink's VRDisplay.cpp.
 static constexpr std::array<uint8_t, 2> kWebVrPosePixelMagicNumbers{{42, 142}};
 
-vr_shell::VrShell* g_instance;
-
-static const char kVrShellUIURL[] = "chrome://vr-shell-ui";
-
 float Distance(const gvr::Vec3f& vec1, const gvr::Vec3f& vec2) {
   float xdiff = (vec1.x - vec2.x);
   float ydiff = (vec1.y - vec2.y);
@@ -147,113 +134,155 @@ std::unique_ptr<blink::WebMouseEvent> MakeMouseEvent(WebInputEvent::Type type,
 
   return mouse_event;
 }
+
+enum class ViewerType {
+  UNKNOWN_TYPE = 0,
+  CARDBOARD = 1,
+  DAYDREAM = 2,
+  VIEWER_TYPE_MAX,
+};
+
+int GetPixelEncodedPoseIndexByte() {
+  TRACE_EVENT0("gpu", "VrShellGl::GetPixelEncodedPoseIndex");
+  // Read the pose index encoded in a bottom left pixel as color values.
+  // See also third_party/WebKit/Source/modules/vr/VRDisplay.cpp which
+  // encodes the pose index, and device/vr/android/gvr/gvr_device.cc
+  // which tracks poses. Returns the low byte (0..255) if valid, or -1
+  // if not valid due to bad magic number.
+  uint8_t pixels[4];
+  // Assume we're reading from the framebuffer we just wrote to.
+  // That's true currently, we may need to use glReadBuffer(GL_BACK)
+  // or equivalent if the rendering setup changes in the future.
+  glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
+
+  // Check for the magic number written by VRDevice.cpp on submit.
+  // This helps avoid glitches from garbage data in the render
+  // buffer that can appear during initialization or resizing. These
+  // often appear as flashes of all-black or all-white pixels.
+  if (pixels[1] == kWebVrPosePixelMagicNumbers[0] &&
+      pixels[2] == kWebVrPosePixelMagicNumbers[1]) {
+    // Pose is good.
+    return pixels[0];
+  }
+  VLOG(1) << "WebVR: reject decoded pose index " << (int)pixels[0] <<
+      ", bad magic number " << (int)pixels[1] << ", " << (int)pixels[2];
+  return -1;
+}
+
 }  // namespace
 
-VrShell::VrShell(JNIEnv* env,
-                 jobject obj,
-                 content::WebContents* main_contents,
-                 ui::WindowAndroid* content_window,
-                 content::WebContents* ui_contents,
-                 ui::WindowAndroid* ui_window,
-                 bool for_web_vr)
-    : WebContentsObserver(ui_contents),
-      main_contents_(main_contents),
-      ui_contents_(ui_contents),
-      metrics_helper_(new VrMetricsHelper(main_contents)),
-      main_thread_task_runner_(base::ThreadTaskRunnerHandle::Get()),
-      weak_ptr_factory_(this) {
-  DCHECK(g_instance == nullptr);
-  g_instance = this;
-  j_vr_shell_.Reset(env, obj);
-  scene_.reset(new UiScene);
+VrShellGl::VrShellGl(
+    VrShell* vr_shell,
+    const base::WeakPtr<VrShell>& weak_vr_shell,
+    const base::WeakPtr<VrInputManager>& content_input_manager,
+    const base::WeakPtr<VrInputManager>& ui_input_manager,
+    scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner,
+    gvr_context* gvr_api)
+      : task_runner_(base::ThreadTaskRunnerHandle::Get()),
+        vr_shell_(vr_shell),
+        weak_vr_shell_(weak_vr_shell),
+        content_input_manager_(content_input_manager),
+        ui_input_manager_(ui_input_manager),
+        main_thread_task_runner_(std::move(main_thread_task_runner)),
+        weak_ptr_factory_(this) {
+  GvrInit(gvr_api);
+}
 
-  if (for_web_vr)
-    metrics_helper_->SetWebVREnabled(true);
-  html_interface_.reset(new UiInterface(
-      for_web_vr ? UiInterface::Mode::WEB_VR : UiInterface::Mode::STANDARD,
-      main_contents_->IsFullscreen()));
-  content_compositor_.reset(new VrCompositor(content_window, false));
-  ui_compositor_.reset(new VrCompositor(ui_window, true));
-  vr_web_contents_observer_.reset(new VrWebContentsObserver(
-      main_contents, html_interface_.get(), this));
+VrShellGl::~VrShellGl() {
+  draw_task_.Cancel();
+}
 
-  LoadUIContentOnUI();
+bool VrShellGl::Initialize() {
+  if (!InitializeGl()) return false;
 
   gvr::Mat4f identity;
   SetIdentityM(identity);
   webvr_head_pose_.resize(kPoseRingBufferSize, identity);
   webvr_head_pose_valid_.resize(kPoseRingBufferSize, false);
 
-  content_input_manager_.reset(new VrInputManager(main_contents_));
-  ui_input_manager_.reset(new VrInputManager(ui_contents_));
-  weak_content_input_manager_ = content_input_manager_->GetWeakPtr();
-  weak_ui_input_manager_ = ui_input_manager_->GetWeakPtr();
+  draw_task_.Reset(base::Bind(&VrShellGl::DrawFrame, base::Unretained(this)));
 
-  SetShowingOverscrollGlowOnUI(false);
-}
+  scene_.reset(new UiScene);
 
-void VrShell::UpdateCompositorLayersOnUI(JNIEnv* env,
-                                     const JavaParamRef<jobject>& obj) {
-  content_compositor_->SetLayer(main_contents_);
-  ui_compositor_->SetLayer(ui_contents_);
-}
+  InitializeRenderer();
 
-void VrShell::DestroyOnUI(JNIEnv* env, const JavaParamRef<jobject>& obj) {
-  delete this;
+  ScheduleNextDrawFrame();
+  return true;
 }
 
-void VrShell::LoadUIContentOnUI() {
-  GURL url(kVrShellUIURL);
-  ui_contents_->GetController().LoadURL(
-      url, content::Referrer(),
-      ui::PageTransition::PAGE_TRANSITION_AUTO_TOPLEVEL, std::string(""));
-}
+bool VrShellGl::InitializeGl() {
+  if (gl::GetGLImplementation() == gl::kGLImplementationNone &&
+      !gl::init::InitializeGLOneOff()) {
+    LOG(ERROR) << "gl::init::InitializeGLOneOff failed";
+    ForceExitVR();
+    return false;
+  }
+  surface_ = gl::init::CreateOffscreenGLSurface(gfx::Size());
+  if (!surface_.get()) {
+    LOG(ERROR) << "gl::init::CreateOffscreenGLSurface failed";
+    ForceExitVR();
+    return false;
+  }
+  context_ = gl::init::CreateGLContext(nullptr, surface_.get(),
+                                       gl::GLContextAttribs());
+  if (!context_.get()) {
+    LOG(ERROR) << "gl::init::CreateGLContext failed";
+    ForceExitVR();
+    return false;
+  }
+  if (!context_->MakeCurrent(surface_.get())) {
+    LOG(ERROR) << "gl::GLContext::MakeCurrent() failed";
+    ForceExitVR();
+    return false;
+  }
 
-bool RegisterVrShell(JNIEnv* env) {
-  return RegisterNativesImpl(env);
+  // TODO(mthiesse): We don't appear to have a VSync provider ever here. This is
+  // sort of okay, because the GVR swap chain will block if we render too fast,
+  // but we should address this properly.
+  if (surface_->GetVSyncProvider()) {
+    surface_->GetVSyncProvider()->GetVSyncParameters(base::Bind(
+        &VrShellGl::UpdateVSyncParameters, weak_ptr_factory_.GetWeakPtr()));
+  } else {
+    LOG(ERROR) << "No VSync Provider";
+  }
+
+  unsigned int textures[2];
+  glGenTextures(2, textures);
+  ui_texture_id_ = textures[0];
+  content_texture_id_ = textures[1];
+  ui_surface_texture_ = gl::SurfaceTexture::Create(ui_texture_id_);
+  content_surface_texture_ = gl::SurfaceTexture::Create(content_texture_id_);
+  ui_surface_.reset(new gl::ScopedJavaSurface(ui_surface_texture_.get()));
+  content_surface_.reset(new gl::ScopedJavaSurface(
+      content_surface_texture_.get()));
+  ui_surface_texture_->SetFrameAvailableCallback(base::Bind(
+        &VrShellGl::OnUIFrameAvailable, weak_ptr_factory_.GetWeakPtr()));
+  content_surface_texture_->SetFrameAvailableCallback(base::Bind(
+        &VrShellGl::OnContentFrameAvailable, weak_ptr_factory_.GetWeakPtr()));
+
+  content_surface_texture_->SetDefaultBufferSize(
+      content_tex_physical_size_.width, content_tex_physical_size_.height);
+  ui_surface_texture_->SetDefaultBufferSize(ui_tex_physical_size_.width,
+                                            ui_tex_physical_size_.height);
+
+  main_thread_task_runner_->PostTask(FROM_HERE, base::Bind(
+      &VrShell::SurfacesChanged, weak_vr_shell_,
+      content_surface_->j_surface().obj(),
+      ui_surface_->j_surface().obj()));
+  return true;
 }
 
-VrShell::~VrShell() {
-  if (delegate_ && delegate_->GetDeviceProvider()) {
-    delegate_->GetDeviceProvider()->OnGvrDelegateRemoved();
-  }
-  g_instance = nullptr;
-  gl::init::ShutdownGL();
+void VrShellGl::OnUIFrameAvailable() {
+  ui_surface_texture_->UpdateTexImage();
 }
 
-void VrShell::SetDelegateOnUI(JNIEnv* env,
-    const base::android::JavaParamRef<jobject>& obj,
-    const base::android::JavaParamRef<jobject>& delegate) {
-  base::AutoLock lock(gvr_init_lock_);
-  delegate_ = VrShellDelegate::GetNativeDelegate(env, delegate);
-  if (swap_chain_.get()) {
-    delegate_->GetDeviceProvider()->OnGvrDelegateReady(
-        weak_ptr_factory_.GetWeakPtr());
-  }
+void VrShellGl::OnContentFrameAvailable() {
+  content_surface_texture_->UpdateTexImage();
 }
 
-enum class ViewerType {
-  UNKNOWN_TYPE = 0,
-  CARDBOARD = 1,
-  DAYDREAM = 2,
-  VIEWER_TYPE_MAX,
-};
-
-void VrShell::GvrInitOnGL(JNIEnv* env,
-                      const JavaParamRef<jobject>& obj,
-                      jlong native_gvr_api) {
-  // set the initial webvr state
-  metrics_helper_->SetVRActive(true);
-
-  gvr_api_ =
-      gvr::GvrApi::WrapNonOwned(reinterpret_cast<gvr_context*>(native_gvr_api));
-  // TODO(klausw,crbug.com/655722): should report OnGvrDelegateReady here once
-  // we switch to using a WebVR render surface. We currently need to wait for
-  // the compositor window's size to be known first. See also
-  // ContentSurfaceChanged.
-  controller_.reset(
-      new VrController(reinterpret_cast<gvr_context*>(native_gvr_api)));
-
+void VrShellGl::GvrInit(gvr_context* gvr_api) {
+  gvr_api_ = gvr::GvrApi::WrapNonOwned(gvr_api);
+  controller_.reset(new VrController(gvr_api));
 
   ViewerType viewerType;
   switch (gvr_api_->GetViewerType()) {
@@ -272,17 +301,7 @@ void VrShell::GvrInitOnGL(JNIEnv* env,
       static_cast<int>(ViewerType::VIEWER_TYPE_MAX));
 }
 
-void VrShell::InitializeGlOnGL(JNIEnv* env,
-                           const JavaParamRef<jobject>& obj,
-                           jint content_texture_handle,
-                           jint ui_texture_handle) {
-  base::AutoLock lock(gvr_init_lock_);
-  CHECK(gl::GetGLImplementation() != gl::kGLImplementationNone ||
-        gl::init::InitializeGLOneOff());
-
-  content_texture_id_ = content_texture_handle;
-  ui_texture_id_ = ui_texture_handle;
-
+void VrShellGl::InitializeRenderer() {
   // While WebVR is going through the compositor path, it shares
   // the same texture ID. This will change once it gets its own
   // surface, but store it separately to avoid future confusion.
@@ -357,41 +376,38 @@ void VrShell::InitializeGlOnGL(JNIEnv* env,
                                            webvr_right_viewport_.get());
   webvr_right_viewport_->SetSourceBufferIndex(kFramePrimaryBuffer);
 
-  if (delegate_) {
-    main_thread_task_runner_->PostTask(
-        FROM_HERE, base::Bind(&device::GvrDeviceProvider::OnGvrDelegateReady,
-                              delegate_->GetDeviceProvider(),
-                              weak_ptr_factory_.GetWeakPtr()));
-  }
+  main_thread_task_runner_->PostTask(FROM_HERE, base::Bind(
+      &VrShell::GvrDelegateReady, weak_vr_shell_));
 }
 
-void VrShell::UpdateControllerOnGL(const gvr::Vec3f& forward_vector) {
+void VrShellGl::UpdateController(const gvr::Vec3f& forward_vector) {
   controller_->UpdateState();
 
 #if defined(ENABLE_VR_SHELL)
+  // TODO(mthiesse): Fix menu button handling, which should be posted to the UI
+  // thread instead of handled here.
+
   // Note that button up/down state is transient, so ButtonUpHappened only
-  // returns
-  // true for a single frame (and we're guaranteed not to miss it).
+  // returns true for a single frame (and we're guaranteed not to miss it).
   if (controller_->ButtonUpHappened(
           gvr::ControllerButton::GVR_CONTROLLER_BUTTON_APP)) {
-    html_interface_->SetMenuMode(!html_interface_->GetMenuMode());
+//    html_interface_->SetMenuMode(!html_interface_->GetMenuMode());
 
     // TODO(mthiesse): The page is no longer visible when in menu mode. We
     // should unfocus or otherwise let it know it's hidden.
-    if (html_interface_->GetMode() == UiInterface::Mode::WEB_VR) {
-      const auto&& task = html_interface_->GetMenuMode() ?
-          &device::GvrDeviceProvider::OnDisplayBlur :
-          &device::GvrDeviceProvider::OnDisplayFocus;
-      main_thread_task_runner_->PostTask(
-          FROM_HERE, base::Bind(task, delegate_->GetDeviceProvider()));
-    }
+//    if (html_interface_->GetMode() == UiInterface::Mode::WEB_VR) {
+//      const auto&& task = html_interface_->GetMenuMode() ?
+//          &device::GvrDeviceProvider::OnDisplayBlur :
+//          &device::GvrDeviceProvider::OnDisplayFocus;
+//      main_thread_task_runner_->PostTask(
+//          FROM_HERE, base::Bind(task, delegate_->GetDeviceProvider()));
+//    }
   }
 #endif
-  if (html_interface_->GetMode() == UiInterface::Mode::WEB_VR) {
+  if (vr_shell_->GetUiInterface()->GetMode() == UiInterface::Mode::WEB_VR) {
     // Process screen touch events for Cardboard button compatibility.
     // Also send tap events for controller "touchpad click" events.
-    if (touch_pending_ ||
-        controller_->ButtonUpHappened(
+    if (touch_pending_ || controller_->ButtonUpHappened(
             gvr::ControllerButton::GVR_CONTROLLER_BUTTON_CLICK)) {
       touch_pending_ = false;
       std::unique_ptr<WebGestureEvent> gesture(new WebGestureEvent());
@@ -401,7 +417,7 @@ void VrShell::UpdateControllerOnGL(const gvr::Vec3f& forward_vector) {
       gesture->type = WebInputEvent::GestureTapDown;
       gesture->x = 0;
       gesture->y = 0;
-      SendGestureOnGL(CONTENT, std::move(gesture));
+      SendGesture(InputTarget::CONTENT, std::move(gesture));
     }
 
     return;
@@ -461,7 +477,7 @@ void VrShell::UpdateControllerOnGL(const gvr::Vec3f& forward_vector) {
   int pixel_x = 0;
   int pixel_y = 0;
   target_element_ = nullptr;
-  InputTarget input_target = NONE;
+  InputTarget input_target = InputTarget::NONE;
 
   for (const auto& plane : scene_->GetUiElements()) {
     if (!plane->visible || !plane->hit_testable) {
@@ -493,15 +509,16 @@ void VrShell::UpdateControllerOnGL(const gvr::Vec3f& forward_vector) {
 
       target_point_ = plane_intersection_point;
       target_element_ = plane.get();
-      input_target = plane->content_quad ? CONTENT : UI;
+      input_target = plane->content_quad ? InputTarget::CONTENT
+                                         : InputTarget::UI;
     }
   }
-  SendEventsToTargetOnGL(input_target, pixel_x, pixel_y);
+  SendEventsToTarget(input_target, pixel_x, pixel_y);
 }
 
-void VrShell::SendEventsToTargetOnGL(InputTarget input_target,
-                                 int pixel_x,
-                                 int pixel_y) {
+void VrShellGl::SendEventsToTarget(InputTarget input_target,
+                                   int pixel_x,
+                                   int pixel_y) {
   std::vector<std::unique_ptr<WebGestureEvent>> gesture_list =
       controller_->DetectGestures();
   double timestamp = gesture_list.front()->timeStampSeconds;
@@ -524,15 +541,15 @@ void VrShell::SendEventsToTargetOnGL(InputTarget input_target,
       case WebInputEvent::GestureScrollEnd:
       case WebInputEvent::GestureFlingCancel:
       case WebInputEvent::GestureFlingStart:
-        SendGestureOnGL(CONTENT,
-                        base::WrapUnique(new WebGestureEvent(*gesture)));
+        SendGesture(InputTarget::CONTENT,
+                    base::WrapUnique(new WebGestureEvent(*gesture)));
         break;
       case WebInputEvent::GestureTapDown:
         gesture->x = pixel_x;
         gesture->y = pixel_y;
-        if (input_target != NONE)
-          SendGestureOnGL(input_target,
-                          base::WrapUnique(new WebGestureEvent(*gesture)));
+        if (input_target != InputTarget::NONE)
+          SendGesture(input_target,
+                      base::WrapUnique(new WebGestureEvent(*gesture)));
         break;
       case WebInputEvent::Undefined:
         break;
@@ -543,66 +560,38 @@ void VrShell::SendEventsToTargetOnGL(InputTarget input_target,
 
   // Hover support
   bool new_target = input_target != current_input_target_;
-  if (new_target && current_input_target_ != NONE) {
+  if (new_target && current_input_target_ != InputTarget::NONE) {
     // Send a move event indicating that the pointer moved off of an element.
-    SendGestureOnGL(current_input_target_,
-                    MakeMouseEvent(WebInputEvent::MouseLeave, timestamp, 0, 0));
+    SendGesture(current_input_target_,
+                MakeMouseEvent(WebInputEvent::MouseLeave, timestamp, 0, 0));
   }
-
   current_input_target_ = input_target;
-  if (current_input_target_ != NONE) {
+  if (current_input_target_ != InputTarget::NONE) {
     WebInputEvent::Type type =
         new_target ? WebInputEvent::MouseEnter : WebInputEvent::MouseMove;
-    SendGestureOnGL(input_target,
-                    MakeMouseEvent(type, timestamp, pixel_x, pixel_y));
+    SendGesture(input_target,
+                MakeMouseEvent(type, timestamp, pixel_x, pixel_y));
   }
 }
 
-void VrShell::SendGestureOnGL(InputTarget input_target,
-                          std::unique_ptr<blink::WebInputEvent> event) {
-  DCHECK(input_target != NONE);
+void VrShellGl::SendGesture(InputTarget input_target,
+                            std::unique_ptr<blink::WebInputEvent> event) {
+  DCHECK(input_target != InputTarget::NONE);
   const base::WeakPtr<VrInputManager>& weak_ptr =
-      input_target == CONTENT ? weak_content_input_manager_
-                              : weak_ui_input_manager_;
+      input_target == InputTarget::CONTENT ? content_input_manager_
+                                           : ui_input_manager_;
   main_thread_task_runner_->PostTask(
       FROM_HERE,
       base::Bind(&VrInputManager::ProcessUpdatedGesture, weak_ptr,
                  base::Passed(std::move(event))));
 }
 
-void VrShell::SetGvrPoseForWebVr(const gvr::Mat4f& pose, uint32_t pose_num) {
+void VrShellGl::SetGvrPoseForWebVr(const gvr::Mat4f& pose, uint32_t pose_num) {
   webvr_head_pose_[pose_num % kPoseRingBufferSize] = pose;
   webvr_head_pose_valid_[pose_num % kPoseRingBufferSize] = true;
 }
 
-int GetPixelEncodedPoseIndexByte() {
-  TRACE_EVENT0("gpu", "VrShell::GetPixelEncodedPoseIndex");
-  // Read the pose index encoded in a bottom left pixel as color values.
-  // See also third_party/WebKit/Source/modules/vr/VRDisplay.cpp which
-  // encodes the pose index, and device/vr/android/gvr/gvr_device.cc
-  // which tracks poses. Returns the low byte (0..255) if valid, or -1
-  // if not valid due to bad magic number.
-  uint8_t pixels[4];
-  // Assume we're reading from the framebuffer we just wrote to.
-  // That's true currently, we may need to use glReadBuffer(GL_BACK)
-  // or equivalent if the rendering setup changes in the future.
-  glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
-
-  // Check for the magic number written by VRDevice.cpp on submit.
-  // This helps avoid glitches from garbage data in the render
-  // buffer that can appear during initialization or resizing. These
-  // often appear as flashes of all-black or all-white pixels.
-  if (pixels[1] == kWebVrPosePixelMagicNumbers[0] &&
-      pixels[2] == kWebVrPosePixelMagicNumbers[1]) {
-    // Pose is good.
-    return pixels[0];
-  }
-  VLOG(1) << "WebVR: reject decoded pose index " << (int)pixels[0] <<
-      ", bad magic number " << (int)pixels[1] << ", " << (int)pixels[2];
-  return -1;
-}
-
-bool VrShell::WebVrPoseByteIsValidOnGL(int pose_index_byte) {
+bool VrShellGl::WebVrPoseByteIsValid(int pose_index_byte) {
   if (pose_index_byte < 0) {
     return false;
   }
@@ -614,29 +603,31 @@ bool VrShell::WebVrPoseByteIsValidOnGL(int pose_index_byte) {
   return true;
 }
 
-void VrShell::DrawFrameOnGL(JNIEnv* env, const JavaParamRef<jobject>& obj) {
-  TRACE_EVENT0("gpu", "VrShell::DrawFrame");
+void VrShellGl::DrawFrame() {
+  TRACE_EVENT0("gpu", "VrShellGl::DrawFrame");
   // Reset the viewport list to just the pair of viewports for the
   // primary buffer each frame. Head-locked viewports get added by
   // DrawVrShell if needed.
   buffer_viewport_list_->SetToRecommendedBufferViewports();
 
-  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_);
-    }
-  } else {
-    if (render_size_primary_ != render_size_primary_vrshell_) {
-      render_size_primary_ = render_size_primary_vrshell_;
-      swap_chain_->ResizeBuffer(kFramePrimaryBuffer, render_size_primary_);
-    }
-  }
+  // TODO(klausw): Fix this. Resizing buffers here leads to webVR mode showing
+  // nothing but a black screen.
+//  if (vr_shell_->GetUiInterface()->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_);
+//    }
+//  } else {
+//    if (render_size_primary_ != render_size_primary_vrshell_) {
+//      render_size_primary_ = render_size_primary_vrshell_;
+//      swap_chain_->ResizeBuffer(kFramePrimaryBuffer, render_size_primary_);
+//    }
+//  }
 
   gvr::Frame frame = swap_chain_->AcquireFrame();
   gvr::ClockTimePoint target_time = gvr::GvrApi::GetTimePointNow();
@@ -655,19 +646,16 @@ void VrShell::DrawFrameOnGL(JNIEnv* env, const JavaParamRef<jobject>& obj) {
     gvr_api_->ApplyNeckModel(head_pose, 1.0f);
   }
 
-  // Bind the primary framebuffer.
   frame.BindBuffer(kFramePrimaryBuffer);
 
-  HandleQueuedTasksOnGL();
-
   // Update the render position of all UI elements (including desktop).
   const float screen_tilt = kDesktopScreenTiltDefault * M_PI / 180.0f;
   scene_->UpdateTransforms(screen_tilt, UiScene::TimeInMicroseconds());
 
-  UpdateControllerOnGL(GetForwardVector(head_pose));
+  UpdateController(GetForwardVector(head_pose));
 
-  if (html_interface_->GetMode() == UiInterface::Mode::WEB_VR) {
-    DrawWebVrOnGL();
+  if (vr_shell_->GetUiInterface()->GetMode() == UiInterface::Mode::WEB_VR) {
+    DrawWebVr();
 
     // When using async reprojection, we need to know which pose was used in
     // the WebVR app for drawing this frame. Due to unknown amounts of
@@ -678,7 +666,7 @@ void VrShell::DrawFrameOnGL(JNIEnv* env, const JavaParamRef<jobject>& obj) {
     // doing this once we have working no-compositor rendering for WebVR.
     if (gvr_api_->GetAsyncReprojectionEnabled()) {
       int pose_index_byte = GetPixelEncodedPoseIndexByte();
-      if (WebVrPoseByteIsValidOnGL(pose_index_byte)) {
+      if (WebVrPoseByteIsValid(pose_index_byte)) {
         // We have a valid pose, use it for reprojection.
         webvr_left_viewport_->SetReprojection(GVR_REPROJECTION_FULL);
         webvr_right_viewport_->SetReprojection(GVR_REPROJECTION_FULL);
@@ -699,15 +687,18 @@ void VrShell::DrawFrameOnGL(JNIEnv* env, const JavaParamRef<jobject>& obj) {
     }
   }
 
-  DrawVrShellOnGL(head_pose, frame);
+  DrawVrShell(head_pose, frame);
 
   frame.Unbind();
   frame.Submit(*buffer_viewport_list_, head_pose);
+
+  // No need to SwapBuffers for an offscreen surface.
+  ScheduleNextDrawFrame();
 }
 
-void VrShell::DrawVrShellOnGL(const gvr::Mat4f& head_pose,
-                          gvr::Frame &frame) {
-  TRACE_EVENT0("gpu", "VrShell::DrawVrShell");
+void VrShellGl::DrawVrShell(const gvr::Mat4f& head_pose,
+                            gvr::Frame &frame) {
+  TRACE_EVENT0("gpu", "VrShellGl::DrawVrShell");
   std::vector<const ContentRectangle*> head_locked_elements;
   std::vector<const ContentRectangle*> world_elements;
   for (const auto& rect : scene_->GetUiElements()) {
@@ -721,7 +712,7 @@ void VrShell::DrawVrShellOnGL(const gvr::Mat4f& head_pose,
     }
   }
 
-  if (html_interface_->GetMode() == UiInterface::Mode::WEB_VR) {
+  if (vr_shell_->GetUiInterface()->GetMode() == UiInterface::Mode::WEB_VR) {
     // WebVR is incompatible with 3D world compositing since the
     // depth buffer was already populated with unknown scaling - the
     // WebVR app has full control over zNear/zFar. Just leave the
@@ -738,9 +729,8 @@ void VrShell::DrawVrShellOnGL(const gvr::Mat4f& head_pose,
     glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
   }
-
   if (!world_elements.empty()) {
-    DrawUiViewOnGL(&head_pose, world_elements, render_size_primary_,
+    DrawUiView(&head_pose, world_elements, render_size_primary_,
                kViewportListPrimaryOffset);
   }
 
@@ -755,33 +745,35 @@ void VrShell::DrawVrShellOnGL(const gvr::Mat4f& head_pose,
         *headlocked_right_viewport_);
 
     // Bind the headlocked framebuffer.
+    // TODO(mthiesse): We don't unbind this? Maybe some cleanup is in order
+    // here.
     frame.BindBuffer(kFrameHeadlockedBuffer);
     glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
-    DrawUiViewOnGL(nullptr, head_locked_elements, render_size_headlocked_,
+    DrawUiView(nullptr, head_locked_elements, render_size_headlocked_,
                kViewportListHeadlockedOffset);
   }
 }
 
-void VrShell::SetWebVRRenderSurfaceSize(int width, int height) {
+void VrShellGl::SetWebVRRenderSurfaceSize(int width, int height) {
   render_size_primary_webvr_.width = width;
   render_size_primary_webvr_.height = height;
   // TODO(klausw,crbug.com/655722): set the WebVR render surface size here once
   // we have that.
 }
 
-gvr::Sizei VrShell::GetWebVRCompositorSurfaceSize() {
+gvr::Sizei VrShellGl::GetWebVRCompositorSurfaceSize() {
   // This is a stopgap while we're using the WebVR compositor rendering path.
   // TODO(klausw,crbug.com/655722): Remove this method and member once we're
   // using a separate WebVR render surface.
   return content_tex_physical_size_;
 }
 
-
-void VrShell::DrawUiViewOnGL(const gvr::Mat4f* head_pose,
-                         const std::vector<const ContentRectangle*>& elements,
-                         const gvr::Sizei& render_size, int viewport_offset) {
-  TRACE_EVENT0("gpu", "VrShell::DrawUiView");
+void VrShellGl::DrawUiView(const gvr::Mat4f* head_pose,
+                           const std::vector<const ContentRectangle*>& elements,
+                           const gvr::Sizei& render_size,
+                           int viewport_offset) {
+  TRACE_EVENT0("gpu", "VrShellGl::DrawUiView");
   for (auto eye : {GVR_LEFT_EYE, GVR_RIGHT_EYE}) {
     buffer_viewport_list_->GetBufferViewport(
         eye + viewport_offset, buffer_viewport_.get());
@@ -802,15 +794,15 @@ void VrShell::DrawUiViewOnGL(const gvr::Mat4f* head_pose,
             buffer_viewport_->GetSourceFov(), kZNear, kZFar),
         view_matrix);
 
-    DrawElementsOnGL(render_matrix, elements);
+    DrawElements(render_matrix, elements);
     if (head_pose != nullptr &&
-        html_interface_->GetMode() != UiInterface::Mode::WEB_VR) {
-      DrawCursorOnGL(render_matrix);
+        vr_shell_->GetUiInterface()->GetMode() != UiInterface::Mode::WEB_VR) {
+      DrawCursor(render_matrix);
     }
   }
 }
 
-void VrShell::DrawElementsOnGL(
+void VrShellGl::DrawElements(
     const gvr::Mat4f& render_matrix,
     const std::vector<const ContentRectangle*>& elements) {
   for (const auto& rect : elements) {
@@ -834,7 +826,7 @@ void VrShell::DrawElementsOnGL(
   }
 }
 
-void VrShell::DrawCursorOnGL(const gvr::Mat4f& render_matrix) {
+void VrShellGl::DrawCursor(const gvr::Mat4f& render_matrix) {
   gvr::Mat4f mat;
   SetIdentityM(mat);
 
@@ -907,8 +899,8 @@ void VrShell::DrawCursorOnGL(const gvr::Mat4f& render_matrix) {
   }
 }
 
-void VrShell::DrawWebVrOnGL() {
-  TRACE_EVENT0("gpu", "VrShell::DrawWebVr");
+void VrShellGl::DrawWebVr() {
+  TRACE_EVENT0("gpu", "VrShellGl::DrawWebVr");
   // Don't need face culling, depth testing, blending, etc. Turn it all off.
   glDisable(GL_CULL_FACE);
   glDepthMask(GL_FALSE);
@@ -926,240 +918,96 @@ void VrShell::DrawWebVrOnGL() {
                                            *webvr_right_viewport_);
 }
 
-void VrShell::OnTriggerEventOnUI(JNIEnv* env,
-                                 const JavaParamRef<jobject>& obj) {
+void VrShellGl::OnTriggerEvent() {
   // Set a flag to handle this on the render thread at the next frame.
   touch_pending_ = true;
 }
 
-void VrShell::OnPauseOnUI(JNIEnv* env, const JavaParamRef<jobject>& obj) {
-  if (gvr_api_ == nullptr)
-    return;
-
-  // TODO(mthiesse): Clean up threading here.
+void VrShellGl::OnPause() {
+  draw_task_.Cancel();
   controller_->OnPause();
   gvr_api_->PauseTracking();
-  SetShowingOverscrollGlowOnUI(true);
-
-  // exit vr session
-  metrics_helper_->SetVRActive(false);
 }
 
-void VrShell::OnResumeOnUI(JNIEnv* env, const JavaParamRef<jobject>& obj) {
-  if (gvr_api_ == nullptr)
-    return;
-
-  // TODO(mthiesse): Clean up threading here.
+void VrShellGl::OnResume() {
   gvr_api_->RefreshViewerProfile();
   gvr_api_->ResumeTracking();
   controller_->OnResume();
-  SetShowingOverscrollGlowOnUI(false);
-
-  // exit vr session
-  metrics_helper_->SetVRActive(true);
+  draw_task_.Reset(base::Bind(&VrShellGl::DrawFrame, base::Unretained(this)));
+  ScheduleNextDrawFrame();
 }
 
-void VrShell::SetShowingOverscrollGlowOnUI(bool showing_glow) {
-  main_contents_->GetRenderWidgetHostView()->SetShowingOverscrollGlow(
-      showing_glow);
-}
-
-base::WeakPtr<VrShell> VrShell::GetWeakPtrOnUI(
-    const content::WebContents* web_contents) {
-  // Ensure that the WebContents requesting the VrShell instance is the one
-  // we created.
-  if (g_instance != nullptr && g_instance->ui_contents_ == web_contents)
-    return g_instance->weak_ptr_factory_.GetWeakPtr();
-  return base::WeakPtr<VrShell>(nullptr);
-}
-
-void VrShell::OnDomContentsLoadedOnUI() {
-  html_interface_->SetURL(main_contents_->GetVisibleURL());
-  html_interface_->SetLoading(main_contents_->IsLoading());
-  html_interface_->OnDomContentsLoaded();
-}
-
-void VrShell::SetWebVrModeOnUI(JNIEnv* env,
-                           const base::android::JavaParamRef<jobject>& obj,
-                           bool enabled) {
-  metrics_helper_->SetWebVREnabled(enabled);
+void VrShellGl::SetWebVrMode(bool enabled) {
   if (enabled) {
-    html_interface_->SetMode(UiInterface::Mode::WEB_VR);
+    vr_shell_->GetUiInterface()->SetMode(UiInterface::Mode::WEB_VR);
   } else {
-    html_interface_->SetMode(UiInterface::Mode::STANDARD);
+    vr_shell_->GetUiInterface()->SetMode(UiInterface::Mode::STANDARD);
   }
 }
 
-void VrShell::SetWebVRSecureOrigin(bool secure_origin) {
-  // TODO(cjgrant): Align this state with the logic that drives the omnibox.
-  html_interface_->SetWebVRSecureOrigin(secure_origin);
-}
-
-void VrShell::SubmitWebVRFrame() {}
-
-void VrShell::UpdateWebVRTextureBounds(const gvr::Rectf& left_bounds,
-                                       const gvr::Rectf& right_bounds) {
+void VrShellGl::UpdateWebVRTextureBounds(const gvr::Rectf& left_bounds,
+                                         const gvr::Rectf& right_bounds) {
   webvr_left_viewport_->SetSourceUv(left_bounds);
   webvr_right_viewport_->SetSourceUv(right_bounds);
 }
 
-gvr::GvrApi* VrShell::gvr_api() {
+gvr::GvrApi* VrShellGl::gvr_api() {
   return gvr_api_.get();
 }
 
-void VrShell::SurfacesChangedOnUI(JNIEnv* env,
-                              const JavaParamRef<jobject>& object,
-                              const JavaParamRef<jobject>& content_surface,
-                              const JavaParamRef<jobject>& ui_surface) {
-  content_compositor_->SurfaceChanged(content_surface);
-  ui_compositor_->SurfaceChanged(ui_surface);
+void VrShellGl::ContentBoundsChanged(int width, int height) {
+  TRACE_EVENT0("gpu", "VrShellGl::ContentBoundsChanged");
+  content_tex_css_width_ = width;
+  content_tex_css_height_ = height;
 }
 
-void VrShell::ContentBoundsChangedOnUI(JNIEnv* env,
-                                   const JavaParamRef<jobject>& object,
-                                   jint width, jint height, jfloat dpr) {
-  TRACE_EVENT0("gpu", "VrShell::ContentBoundsChanged");
+void VrShellGl::ContentPhysicalBoundsChanged(int width, int height) {
+  if (content_surface_texture_.get())
+    content_surface_texture_->SetDefaultBufferSize(width, height);
   content_tex_physical_size_.width = width;
   content_tex_physical_size_.height = height;
-  // TODO(mthiesse): Synchronize with GL thread, and update tex css size in
-  // response to MainFrameWasResized, not here.
-  content_tex_css_width_ = width / dpr;
-  content_tex_css_height_ = height / dpr;
-
-  content_compositor_->SetWindowBounds(width, height);
 }
 
-void VrShell::UIBoundsChangedOnUI(JNIEnv* env,
-                              const JavaParamRef<jobject>& object,
-                              jint width, jint height, jfloat dpr) {
-  ui_compositor_->SetWindowBounds(width, height);
+void VrShellGl::UIBoundsChanged(int width, int height) {
+  ui_tex_css_width_ = width;
+  ui_tex_css_height_ = height;
 }
 
-UiScene* VrShell::GetSceneOnGL() {
-  return scene_.get();
+void VrShellGl::UIPhysicalBoundsChanged(int width, int height) {
+  if (ui_surface_texture_.get())
+    ui_surface_texture_->SetDefaultBufferSize(width, height);
+  ui_tex_physical_size_.width = width;
+  ui_tex_physical_size_.height = height;
 }
 
-UiInterface* VrShell::GetUiInterfaceOnGL() {
-  return html_interface_.get();
+base::WeakPtr<VrShellGl> VrShellGl::GetWeakPtr() {
+  return weak_ptr_factory_.GetWeakPtr();
 }
 
-void VrShell::QueueTaskOnUI(base::Callback<void()>& callback) {
-  base::AutoLock lock(task_queue_lock_);
-  task_queue_.push(callback);
+void VrShellGl::UpdateVSyncParameters(const base::TimeTicks timebase,
+                                      const base::TimeDelta interval) {
+  vsync_timebase_ = timebase;
+  vsync_interval_ = interval;
 }
 
-void VrShell::HandleQueuedTasksOnGL() {
-  // To protect a stream of tasks from blocking rendering indefinitely,
-  // process only the number of tasks present when first checked.
-  std::vector<base::Callback<void()>> tasks;
-  {
-    base::AutoLock lock(task_queue_lock_);
-    const size_t count = task_queue_.size();
-    for (size_t i = 0; i < count; i++) {
-      tasks.push_back(task_queue_.front());
-      task_queue_.pop();
-    }
-  }
-  for (auto &task : tasks) {
-    task.Run();
-  }
-}
+void VrShellGl::ScheduleNextDrawFrame() {
+  base::TimeTicks now = base::TimeTicks::Now();
+  base::TimeTicks target;
 
-void VrShell::DoUiActionOnUI(const UiAction action) {
-  content::NavigationController& controller = main_contents_->GetController();
-  switch (action) {
-    case HISTORY_BACK:
-      if (main_contents_->IsFullscreen()) {
-        main_contents_->ExitFullscreen(true /* will_cause_resize */);
-      } else if (controller.CanGoBack()) {
-        controller.GoBack();
-      }
-      break;
-    case HISTORY_FORWARD:
-      if (controller.CanGoForward())
-        controller.GoForward();
-      break;
-    case RELOAD:
-      controller.Reload(false);
-      break;
-#if defined(ENABLE_VR_SHELL_UI_DEV)
-    case RELOAD_UI:
-      ui_contents_->GetController().Reload(false);
-      html_interface_.reset(new UiInterface(UiInterface::Mode::STANDARD,
-                                            main_contents_->IsFullscreen()));
-      vr_web_contents_observer_->SetUiInterface(html_interface_.get());
-      break;
-#endif
-    case ZOOM_OUT:  // Not handled yet.
-    case ZOOM_IN:  // Not handled yet.
-      break;
-    default:
-      NOTREACHED();
+  if (vsync_interval_.is_zero()) {
+    target = now;
+  } else {
+    target = now + vsync_interval_;
+    int64_t intervals = (target - vsync_timebase_) / vsync_interval_;
+    target = vsync_timebase_ + intervals * vsync_interval_;
   }
-}
-
-void VrShell::RenderViewHostChanged(content::RenderViewHost* old_host,
-                                    content::RenderViewHost* new_host) {
-  new_host->GetWidget()->GetView()->SetBackgroundColor(SK_ColorTRANSPARENT);
-}
-
-void VrShell::MainFrameWasResized(bool width_changed) {
-  display::Display display = display::Screen::GetScreen()
-      ->GetDisplayNearestWindow(ui_contents_->GetNativeView());
-  // TODO(mthiesse): Synchronize with GL thread.
-  ui_tex_css_width_ = display.size().width();
-  ui_tex_css_height_ = display.size().height();
-}
 
-void VrShell::WebContentsDestroyed() {
-  ui_input_manager_.reset();
-  ui_contents_ = nullptr;
-  // TODO(mthiesse): Handle web contents being destroyed.
-  delegate_->ForceExitVr();
+  task_runner_->PostDelayedTask(FROM_HERE, draw_task_.callback(), target - now);
 }
 
-void VrShell::ContentWebContentsDestroyedOnUI() {
-  content_input_manager_.reset();
-  main_contents_ = nullptr;
-  // TODO(mthiesse): Handle web contents being destroyed.
-  delegate_->ForceExitVr();
-}
-
-void VrShell::ContentWasHiddenOnUI() {
-  // Ensure we don't continue sending input to it.
-  content_input_manager_.reset();
-  // TODO(mthiesse): Handle web contents being hidden.
-  delegate_->ForceExitVr();
-}
-
-void VrShell::SetContentCssSizeOnUI(float width, float height, float dpr) {
-  JNIEnv* env = base::android::AttachCurrentThread();
-  Java_VrShellImpl_setContentCssSizeOnUI(env, j_vr_shell_.obj(), width, height,
-                                         dpr);
-}
-
-void VrShell::SetUiCssSizeOnUI(float width, float height, float dpr) {
-  JNIEnv* env = base::android::AttachCurrentThread();
-  Java_VrShellImpl_setUiCssSizeOnUI(env, j_vr_shell_.obj(), width, height, dpr);
-}
-
-// ----------------------------------------------------------------------------
-// Native JNI methods
-// ----------------------------------------------------------------------------
-
-jlong InitOnUI(JNIEnv* env,
-               const JavaParamRef<jobject>& obj,
-               const JavaParamRef<jobject>& content_web_contents,
-               jlong content_window_android,
-               const JavaParamRef<jobject>& ui_web_contents,
-               jlong ui_window_android,
-               jboolean for_web_vr) {
-  return reinterpret_cast<intptr_t>(new VrShell(
-      env, obj, content::WebContents::FromJavaWebContents(content_web_contents),
-      reinterpret_cast<ui::WindowAndroid*>(content_window_android),
-      content::WebContents::FromJavaWebContents(ui_web_contents),
-      reinterpret_cast<ui::WindowAndroid*>(ui_window_android),
-      for_web_vr));
+void VrShellGl::ForceExitVR() {
+  main_thread_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&VrShell::ForceExitVR, weak_vr_shell_));
 }
 
 }  // namespace vr_shell