VrShell: implement insecure content warning display

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 947645f82e66632acb4ee8f69ed5721da5fd7bb1..3b692e1534d992900a4419595d188a0858e4d86b 100644
--- a/chrome/browser/android/vr_shell/vr_shell.cc
+++ b/chrome/browser/android/vr_shell/vr_shell.cc
@@ -226,6 +226,9 @@ void VrShell::DrawFrame(JNIEnv* env, const JavaParamRef<jobject>& obj) {
 
   if (webvr_mode_) {
     DrawWebVr();
+    if (!webvr_secure_origin_) {
+      DrawWebVrOverlay();
+    }
   } else {
     DrawVrShell(target_time.monotonic_system_time_nanos);
   }
@@ -388,10 +391,76 @@ void VrShell::DrawWebVr() {
 
   glViewport(0, 0, render_size_.width, render_size_.height);
   vr_shell_renderer_->GetWebVrRenderer()->Draw(content_texture_id_);
+}
 
-  if (!webvr_secure_origin_) {
-    // TODO(klausw): Draw the insecure origin warning here.
+void VrShell::DrawWebVrOverlay() {
+  // Draw WebVR security warning overlays for each eye. This uses
+  // the eye-from-head matrices but not the pose, goal is to place
+  // the icons in an eye-relative position so that they follow along
+  // with head rotations.
+
+  gvr::Mat4f left_eye_view_matrix =
+      gvr_api_->GetEyeFromHeadMatrix(GVR_LEFT_EYE);
+  gvr::Mat4f right_eye_view_matrix =
+      gvr_api_->GetEyeFromHeadMatrix(GVR_RIGHT_EYE);
+
+  buffer_viewport_list_->GetBufferViewport(GVR_LEFT_EYE,
+                                           buffer_viewport_.get());
+  DrawWebVrEye(left_eye_view_matrix, *buffer_viewport_);
+  buffer_viewport_list_->GetBufferViewport(GVR_RIGHT_EYE,
+                                           buffer_viewport_.get());
+  DrawWebVrEye(right_eye_view_matrix, *buffer_viewport_);
+}
+
+void VrShell::DrawWebVrEye(const gvr::Mat4f& view_matrix,
+                           const gvr::BufferViewport& params) {
+  gvr::Recti pixel_rect =
+      CalculatePixelSpaceRect(render_size_, params.GetSourceUv());
+  glViewport(pixel_rect.left, pixel_rect.bottom,
+             pixel_rect.right - pixel_rect.left,
+             pixel_rect.top - pixel_rect.bottom);
+  glScissor(pixel_rect.left, pixel_rect.bottom,
+            pixel_rect.right - pixel_rect.left,
+            pixel_rect.top - pixel_rect.bottom);
+
+  gvr::Mat4f projection_matrix =
+      PerspectiveMatrixFromView(params.GetSourceFov(), kZNear, kZFar);
+
+  // Draw insecure content warning icons.
+  const float warning_depth = 0.7f;  // Distance in meters.
+
+  // Show IDS_WEBSITE_SETTINGS_INSECURE_WEBVR_CONTENT_PERMANENT text.
+  gvr::Mat4f icon_pos;
+  SetIdentityM(icon_pos);
+  const float small_icon_width = 0.15f * warning_depth;
+  const float small_icon_height = small_icon_width / 2.0f;  // 2:1 aspect.
+  const float small_icon_angle = 20.0f * M_PI / 180.f;  // Degrees to radians.
+  ScaleM(icon_pos, icon_pos, small_icon_width, small_icon_height, 1.0f);
+  TranslateM(icon_pos, icon_pos, 0.0f, 0.0f, -warning_depth);
+  icon_pos = MatrixMul(
+      QuatToMatrix(QuatFromAxisAngle(1.f, 0.f, 0.f, small_icon_angle)),
+      icon_pos);
+  gvr::Mat4f combined = MatrixMul(projection_matrix,
+                                  MatrixMul(view_matrix, icon_pos));
+  vr_shell_renderer_->GetOverlayIconRenderer()->Draw(
+      combined, ICON_INSECURE_PERMANENT);
+
+  // Do we need to show the transient warning also?
+  if (webvr_warning_frames_ == 0) {
+    return;
   }
+  --webvr_warning_frames_;
+
+  // Show IDS_WEBSITE_SETTINGS_INSECURE_WEBVR_CONTENT_TRANSIENT text.
+  SetIdentityM(icon_pos);
+  const float large_icon_width = 0.25f * warning_depth;
+  const float large_icon_height = large_icon_width / 2.0f;  // 2:1 aspect.
+  ScaleM(icon_pos, icon_pos, large_icon_width, large_icon_height, 1.0f);
+  TranslateM(icon_pos, icon_pos, 0.0f, 0.0f, -warning_depth);
+  combined = MatrixMul(projection_matrix,
+                       MatrixMul(view_matrix, icon_pos));
+  vr_shell_renderer_->GetOverlayIconRenderer()->Draw(
+      combined, ICON_INSECURE_TRANSIENT);
 }
 
 void VrShell::OnPause(JNIEnv* env, const JavaParamRef<jobject>& obj) {
@@ -430,6 +499,12 @@ void VrShell::SetWebVrMode(JNIEnv* env,
                            const base::android::JavaParamRef<jobject>& obj,
                            bool enabled) {
   webvr_mode_ = enabled;
+  if (enabled) {
+    const int warning_seconds = 30;
+    webvr_warning_frames_ = warning_seconds * 60;

[billorr, 2016/09/23 17:52:11]

how often do we miss frames?  can we keep the warning up based on seconds
instead of frames?

+  } else {
+    webvr_warning_frames_ = 0;
+  }
 }
 
 void VrShell::SetWebVRSecureOrigin(bool secure_origin) {