Implement WebVR presentation pausing for VR Shell Menu Mode

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 4416da93a63b0f6e05bb76957de9c43796284bf2..e64dc01e70ca52c99b02f8910bc9974739187f3d 100644
--- a/chrome/browser/android/vr_shell/vr_shell.cc
+++ b/chrome/browser/android/vr_shell/vr_shell.cc
@@ -22,6 +22,7 @@
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/referrer.h"
 #include "content/public/common/screen_info.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"
@@ -186,8 +187,7 @@ void VrShell::SetDelegate(JNIEnv* env,
   delegate_ = VrShellDelegate::getNativeDelegate(env, delegate);
 }
 
-enum class ViewerType
-{
+enum class ViewerType {
   UNKNOWN_TYPE = 0,
   CARDBOARD = 1,
   DAYDREAM = 2,
@@ -208,8 +208,7 @@ void VrShell::GvrInit(JNIEnv* env,
   ui_input_manager_ = new VrInputManager(ui_contents_);
 
   ViewerType viewerType;
-  switch (gvr_api_->GetViewerType())
-  {
+  switch (gvr_api_->GetViewerType()) {
     case gvr::ViewerType::GVR_VIEWER_TYPE_DAYDREAM:
       viewerType = ViewerType::DAYDREAM;
       break;
@@ -271,7 +270,32 @@ void VrShell::InitializeGl(JNIEnv* env,
 void VrShell::UpdateController(const gvr::Vec3f& forward_vector) {
   controller_->UpdateState();
   std::unique_ptr<WebGestureEvent> gesture = controller_->DetectGesture();
-
+#if defined(ENABLE_VR_SHELL)
+  // Note that button up/down state is transient, so IsButtonUp only returns
+  // true for a single frame (and we're guaranteed not to miss it).
+  if (controller_->IsButtonUp(
+      gvr::ControllerButton::GVR_CONTROLLER_BUTTON_APP)) {
+    if (html_interface_->GetMode() == UiInterface::Mode::MENU) {
+      // Temporary: Hit app button a second time to exit menu mode.
+      if (webvr_mode_) {
+        html_interface_->SetMode(UiInterface::Mode::WEB_VR);
+        delegate_->GetDeviceProvider()->OnDisplayFocus();
+      } else {
+        html_interface_->SetMode(UiInterface::Mode::STANDARD);
+      }
+    } else {
+      if (html_interface_->GetMode() == UiInterface::Mode::WEB_VR) {
+        delegate_->GetDeviceProvider()->OnDisplayBlur();
+      }
+      html_interface_->SetMode(UiInterface::Mode::MENU);
+      // TODO(mthiesse): The page is no longer visible here. We should unfocus
+      // or otherwise let it know it's hidden.
+    }
+  }
+#endif
+  if (html_interface_->GetMode() == UiInterface::Mode::WEB_VR) {
+    return;
+  }
   // TODO(asimjour) for now, scroll is sent to the main content.
   if (gesture->type == WebInputEvent::GestureScrollBegin ||
       gesture->type == WebInputEvent::GestureScrollUpdate ||
@@ -411,7 +435,7 @@ uint32_t GetPixelEncodedPoseIndex() {
   // encodes the pose index, and device/vr/android/gvr/gvr_device.cc
   // which tracks poses.
   uint8_t pixels[4];
-  // Assume we're reading from the frambebuffer we just wrote to.
+  // 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);
@@ -449,7 +473,7 @@ void VrShell::DrawFrame(JNIEnv* env, const JavaParamRef<jobject>& obj) {
 
   UpdateController(GetForwardVector(head_pose));
 
-  if (webvr_mode_) {
+  if (html_interface_->GetMode() == UiInterface::Mode::WEB_VR) {
     DrawWebVr();
 
     // When using async reprojection, we need to know which pose was used in
@@ -486,16 +510,16 @@ void VrShell::DrawVrShell(const gvr::Mat4f& head_pose,
     }
   }
 
-  if (!webvr_mode_) {
+  bool not_web_vr = html_interface_->GetMode() != UiInterface::Mode::WEB_VR;
+
+  if (not_web_vr) {
     glEnable(GL_CULL_FACE);
     glEnable(GL_DEPTH_TEST);
     glEnable(GL_SCISSOR_TEST);
     glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
   }
 
-  if (!world_elements.empty()) {
-    DrawUiView(&head_pose, world_elements);
-  }
+  DrawUiView(&head_pose, world_elements, not_web_vr);
 
   if (!head_locked_elements.empty()) {
     // Switch to head-locked viewports.
@@ -507,14 +531,14 @@ void VrShell::DrawVrShell(const gvr::Mat4f& head_pose,
 
     // Bind the headlocked framebuffer.
     frame.BindBuffer(kFrameHeadlockedBuffer);
-    glClear(GL_COLOR_BUFFER_BIT);
-
-    DrawUiView(nullptr, head_locked_elements);
+    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+    DrawUiView(nullptr, head_locked_elements, true);
   }
 }
 
 void VrShell::DrawUiView(const gvr::Mat4f* head_pose,
-                         const std::vector<const ContentRectangle*>& elements) {
+                         const std::vector<const ContentRectangle*>& elements,
+                         bool clear) {
   for (auto eye : {GVR_LEFT_EYE, GVR_RIGHT_EYE}) {
     buffer_viewport_list_->GetBufferViewport(eye, buffer_viewport_.get());
 
@@ -532,7 +556,7 @@ void VrShell::DrawUiView(const gvr::Mat4f* head_pose,
               pixel_rect.right - pixel_rect.left,
               pixel_rect.top - pixel_rect.bottom);
 
-    if (!webvr_mode_) {
+    if (clear) {
       glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
     }
 
@@ -655,9 +679,6 @@ void VrShell::DrawWebVr() {
   glDisable(GL_BLEND);
   glDisable(GL_POLYGON_OFFSET_FILL);
 
-  // Don't need to clear, since we're drawing over the entire render target.
-  glClear(GL_COLOR_BUFFER_BIT);
-
   glViewport(0, 0, render_size_.width, render_size_.height);
   vr_shell_renderer_->GetWebVrRenderer()->Draw(content_texture_id_);
 }