Update the UI examples.

examples/ui/shapes/shapes_view.cc

+// Copyright 2015 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 "examples/ui/shapes/shapes_view.h"
+
+#include "base/bind.h"
+#include "base/logging.h"
+#include "third_party/skia/include/core/SkCanvas.h"
+#include "third_party/skia/include/core/SkColor.h"
+#include "third_party/skia/include/core/SkSurface.h"
+
+namespace examples {
+
+constexpr uint32_t kContentImageResourceId = 1;
+constexpr uint32_t kRootNodeId = mojo::gfx::composition::kSceneRootNodeId;
+
+ShapesView::ShapesView(
+    mojo::ApplicationImpl* app_impl,
+    const mojo::ui::ViewProvider::CreateViewCallback& create_view_callback)
+    : GaneshView(app_impl, "Shapes", create_view_callback) {}
+
+ShapesView::~ShapesView() {}
+
+void ShapesView::OnLayout(mojo::ui::ViewLayoutParamsPtr layout_params,
+                          mojo::Array<uint32_t> children_needing_layout,
+                          const OnLayoutCallback& callback) {
+  size_.width = layout_params->constraints->max_width;
+  size_.height = layout_params->constraints->max_height;
+
+  // Submit the new layout information.
+  auto info = mojo::ui::ViewLayoutResult::New();
+  info->size = size_.Clone();
+  callback.Run(info.Pass());
+
+  // Draw!
+  UpdateScene();
+}
+
+void ShapesView::UpdateScene() {
+  mojo::Rect bounds;
+  bounds.width = size_.width;
+  bounds.height = size_.height;
+
+  auto update = mojo::gfx::composition::SceneUpdate::New();

[viettrungluu, 2016/01/13 00:10:57]

Since this is a basic example, a few more (brief) comments might be nice.

[jeffbrown, 2016/01/26 08:14:17]

Done.

+  mojo::gfx::composition::ResourcePtr content_resource =
+      ganesh_renderer()->DrawCanvas(
+          size_, base::Bind(&ShapesView::DrawContent, base::Unretained(this)));
+  DCHECK(content_resource);
+  update->resources.insert(kContentImageResourceId, content_resource.Pass());
+
+  auto root_node = mojo::gfx::composition::Node::New();
+  root_node->op = mojo::gfx::composition::NodeOp::New();
+  root_node->op->set_image(mojo::gfx::composition::ImageNodeOp::New());
+  root_node->op->get_image()->content_rect = bounds.Clone();
+  root_node->op->get_image()->image_resource_id = kContentImageResourceId;
+  update->nodes.insert(kRootNodeId, root_node.Pass());
+
+  scene()->Update(update.Pass());
+  scene()->Publish(nullptr);
+}
+
+void ShapesView::DrawContent(SkCanvas* canvas) {
+  canvas->clear(SK_ColorCYAN);
+
+  SkPaint paint;
+  paint.setColor(SK_ColorGREEN);
+  SkRect rect = SkRect::MakeWH(size_.width, size_.height);
+  rect.inset(10, 10);
+  canvas->drawRect(rect, paint);
+
+  paint.setColor(SK_ColorRED);
+  paint.setFlags(SkPaint::kAntiAlias_Flag);
+  canvas->drawCircle(50, 100, 100, paint);
+
+  canvas->flush();
+}
+
+}  // namespace examples