[vr] Ensure that textured elements never draw with a dirty texture

chrome/browser/android/vr_shell/ui_elements/textured_element.cc

Index: chrome/browser/android/vr_shell/ui_elements/textured_element.cc
diff --git a/chrome/browser/android/vr_shell/ui_elements/textured_element.cc b/chrome/browser/android/vr_shell/ui_elements/textured_element.cc
index e0a7a168f9546b1038c3694e415be72bc2e78a3c..a20da3a5bc833a827238ba3cfb95fbd28dc72bbd 100644
--- a/chrome/browser/android/vr_shell/ui_elements/textured_element.cc
+++ b/chrome/browser/android/vr_shell/ui_elements/textured_element.cc
@@ -50,6 +50,7 @@ void TexturedElement::Render(UiElementRenderer* renderer,
                              gfx::Transform view_proj_matrix) const {
   if (!initialized_)
     return;
+  DCHECK(!GetTexture()->dirty());
   gfx::SizeF drawn_size = GetTexture()->GetDrawnSize();
   gfx::RectF copy_rect(0, 0, drawn_size.width() / texture_size_.width(),
                        drawn_size.height() / texture_size_.height());
@@ -77,4 +78,8 @@ void TexturedElement::OnSetMode() {
   UpdateTexture();
 }
 
+void TexturedElement::OnBeginFrame(const base::TimeTicks& begin_frame_time) {
+  UpdateTexture();
+}
+
 }  // namespace vr_shell