VR: Add a loading indicator to the scene.

chrome/browser/android/vr_shell/textures/loading_indicator_texture.cc

+// 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.
+
+#include "chrome/browser/android/vr_shell/textures/loading_indicator_texture.h"
+
+#include "base/logging.h"
+#include "cc/paint/skia_paint_canvas.h"
+#include "third_party/skia/include/core/SkCanvas.h"
+#include "third_party/skia/include/core/SkColor.h"
+
+namespace vr_shell {
+
+namespace {
+
+static constexpr SkColor kBackground = 0xCCAAAAAA;
+static constexpr SkColor kForeground = 0xCC444444;
+static constexpr float kWidth = 0.268;
+static constexpr float kHeight = 0.008;
+
+}  // namespace
+
+LoadingIndicatorTexture::LoadingIndicatorTexture() = default;
+
+LoadingIndicatorTexture::~LoadingIndicatorTexture() = default;
+
+gfx::Size LoadingIndicatorTexture::GetPreferredTextureSize(
+    int maximum_width) const {
+  return gfx::Size(maximum_width, maximum_width * kHeight / kWidth);
+}
+
+gfx::SizeF LoadingIndicatorTexture::GetDrawnSize() const {
+  return size_;
+}
+
+void LoadingIndicatorTexture::SetLoading(bool loading) {
+  loading_ = loading;
+}
+
+void LoadingIndicatorTexture::SetLoadProgress(float progress) {
+  DCHECK_GE(progress, 0.0f);
+  DCHECK_LE(progress, 1.0f);
+  progress_ = progress;
+}
+
+void LoadingIndicatorTexture::Draw(SkCanvas* canvas,
+                                   const gfx::Size& texture_size) {
+  size_.set_height(texture_size.height());
+  size_.set_width(texture_size.width());
+
+  canvas->save();
+  canvas->scale(size_.width() / kWidth, size_.width() / kWidth);
+
+  SkPaint paint;
+  paint.setColor(kBackground);
+  canvas->drawRoundRect({0, 0, kWidth, kHeight}, kHeight / 2, kHeight / 2,
+                        paint);
+
+  if (loading_) {
+    paint.setColor(kForeground);
+    float progress_width = kHeight + (kWidth - kHeight) * progress_;
+    canvas->drawRoundRect({0, 0, progress_width, kHeight}, kHeight / 2,
+                          kHeight / 2, paint);
+  }
+
+  canvas->restore();
+}
+
+}  // namespace vr_shell