Add a simple compositor for Sky

examples/sky_compositor_app/sky_compositor_app.cc

+// Copyright 2014 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 "base/macros.h"
+#include "mojo/application/application_runner_chromium.h"
+#include "mojo/public/c/system/main.h"
+#include "mojo/public/cpp/application/application_connection.h"
+#include "mojo/public/cpp/application/application_delegate.h"
+#include "mojo/public/cpp/application/application_impl.h"
+#include "mojo/services/public/cpp/view_manager/view.h"
+#include "mojo/services/public/cpp/view_manager/view_manager.h"
+#include "mojo/services/public/cpp/view_manager/view_manager_client_factory.h"
+#include "mojo/services/public/cpp/view_manager/view_manager_delegate.h"
+#include "sky/compositor/layer.h"
+#include "sky/compositor/layer_host.h"
+#include "third_party/skia/include/core/SkCanvas.h"
+
+namespace examples {
+namespace {
+
+gfx::Size ToSize(const mojo::Rect& rect) {

[eseidel, 2014/11/20 20:40:31]

Lame you have to define this yourself.  Does mojo::Rect not make it possible to
add a size() method?

[abarth-chromium, 2014/11/20 20:47:57]

mojo::Rect doesn't have any helper functions.  The idea is that you're supposed
to convert to your own Rect type (e.g., gfx::Rect).

+  return gfx::Size(rect.width, rect.height);
+}
+}
+
+class SkyCompositorApp : public mojo::ApplicationDelegate,
+                         public mojo::ViewManagerDelegate,
+                         public sky::LayerClient,
+                         public sky::LayerHostClient {
+ public:
+  SkyCompositorApp() : shell_(nullptr), view_(nullptr) {}
+  virtual ~SkyCompositorApp() {}
+
+  void Initialize(mojo::ApplicationImpl* app) override {
+    shell_ = app->shell();
+    view_manager_client_factory_.reset(
+        new mojo::ViewManagerClientFactory(app->shell(), this));
+  }
+
+  bool ConfigureIncomingConnection(
+      mojo::ApplicationConnection* connection) override {
+    connection->AddService(view_manager_client_factory_.get());
+    return true;
+  }
+
+  void OnEmbed(mojo::ViewManager* view_manager,
+               mojo::View* root,
+               mojo::ServiceProviderImpl* exported_services,
+               scoped_ptr<mojo::ServiceProvider> imported_services) override {
+    view_ = root;
+
+    layer_host_.reset(new sky::LayerHost(this));
+    root_layer_ = make_scoped_refptr(new sky::Layer(this));

[eseidel, 2014/11/20 20:40:31]

What's with the lower_case_method?

[abarth-chromium, 2014/11/20 20:47:57]

It's supposed to be an analogy to make_unique_ptr and make_shared_ptr from STL.

+    layer_host_->SetRootLayer(root_layer_);
+  }
+
+  void OnViewManagerDisconnected(mojo::ViewManager* view_manager) override {
+    base::MessageLoop::current()->Quit();

[eseidel, 2014/11/20 20:40:31]

AppManager::Terminate or some such.  Look at what debugger.cc does.

[abarth-chromium, 2014/11/20 22:07:20]

Done.

+  }
+
+ private:
+  // sky::LayerHostClient
+  mojo::Shell* GetShell() override { return shell_; }

[eseidel, 2014/11/20 20:40:31]

Style explosion.  I thought this was Shell()?

+
+  void BeginFrame() override { root_layer_->SetSize(ToSize(view_->bounds())); }
+
+  void OnSurfaceIdAvailable(mojo::SurfaceIdPtr surface_id) override {
+    view_->SetSurfaceId(surface_id.Pass());
+  }
+
+  // sky::LayerHostClient

[ojan, 2014/11/20 21:25:46]

// sky::LayerClient ?

[abarth-chromium, 2014/11/20 22:07:20]

Done.

+  void PaintContents(SkCanvas* canvas, const gfx::Rect& clip) override {
+    SkPaint paint;
+    paint.setColor(SK_ColorGREEN);
+    paint.setFlags(SkPaint::kAntiAlias_Flag);
+    canvas->drawCircle(50, 100, 100, paint);
+  }
+
+  mojo::Shell* shell_;
+  scoped_ptr<mojo::ViewManagerClientFactory> view_manager_client_factory_;
+  mojo::View* view_;
+
+  scoped_ptr<sky::LayerHost> layer_host_;
+  scoped_refptr<sky::Layer> root_layer_;
+
+  DISALLOW_COPY_AND_ASSIGN(SkyCompositorApp);
+};
+
+}  // namespace examples
+
+MojoResult MojoMain(MojoHandle handle) {
+  mojo::ApplicationRunnerChromium runner(new examples::SkyCompositorApp);
+  return runner.Run(handle);
+}