VR: Add a loading indicator to the scene.

chrome/browser/android/vr_shell/ui_elements/loading_indicator.h

+// Copyright 2017 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.
+
+#ifndef CHROME_BROWSER_ANDROID_VR_SHELL_UI_ELEMENTS_LOADING_INDICATOR_H_
+#define CHROME_BROWSER_ANDROID_VR_SHELL_UI_ELEMENTS_LOADING_INDICATOR_H_
+
+#include <memory>
+
+#include "base/macros.h"
+#include "base/timer/timer.h"
+#include "chrome/browser/android/vr_shell/ui_elements/textured_element.h"
+
+namespace vr_shell {
+
+class LoadingIndicatorTexture;
+
+class LoadingIndicator : public TexturedElement {
+ public:
+  explicit LoadingIndicator(int preferred_width);
+  ~LoadingIndicator() override;
+
+  void SetLoading(bool loading);
+  void SetLoadProgress(float progress);
+
+  void SetEnabled(bool enabled) override;
+  void OnBeginFrame(const base::TimeTicks& ticks) override;
+
+ private:
+  UiTexture* GetTexture() const override;
+  std::unique_ptr<LoadingIndicatorTexture> texture_;
+
+  void ResetVisibilityTimer();
+  void SetVisibility();
+
+  base::OneShotTimer visibility_timer_;
+  bool enabled_ = false;
+  bool loading_ = false;
+
+  DISALLOW_COPY_AND_ASSIGN(LoadingIndicator);
+};
+
+}  // namespace vr_shell
+
+#endif  // CHROME_BROWSER_ANDROID_VR_SHELL_UI_ELEMENTS_LOADING_INDICATOR_H_