Add BlimpDocument, pull out functions in BlimpCompositor.

blimp/client/core/render_widget/blimp_document.h

+// Copyright 2016 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 BLIMP_CLIENT_CORE_RENDER_WIDGET_BLIMP_DOCUMENT_H_
+#define BLIMP_CLIENT_CORE_RENDER_WIDGET_BLIMP_DOCUMENT_H_
+
+#include <memory>
+
+#include "base/macros.h"
+#include "base/memory/ptr_util.h"
+#include "blimp/client/core/compositor/blimp_compositor.h"
+
+namespace blimp {
+namespace client {
+
+class BlimpCompositorDependencies;
+class BlimpDocumentManager;
+
+// BlimpDocument maps to an engine side render widget.
+// 1. Is created on receiving an RenderWidgetMessage from the engine.
+// 2. Owns the BlimpCompositor instance.
+class BlimpDocument : public BlimpCompositorClient {
+ public:
+  BlimpDocument(int render_widget_id,
+                BlimpCompositorDependencies* compositor_dependencies,
+                BlimpDocumentManager* document_manager);
+  ~BlimpDocument() override;
+
+  int render_widget_id() const { return render_widget_id_; }
+
+  // Returns the compositor instance.
+  BlimpCompositor* GetCompositor();
+
+ protected:
+  void SetCompositorForTest(std::unique_ptr<BlimpCompositor> compositor);
+
+ private:
+  // BlimpCompositorClient implementation.
+  void SendWebGestureEvent(
+      const blink::WebGestureEvent& gesture_event) override;
+  void SendCompositorMessage(
+      const cc::proto::CompositorMessage& message) override;
+
+  // The unique identifier for this document instance.
+  const int render_widget_id_;

[Khushal, 2016/10/03 20:04:59]

Should we rename this to document id in that case?

[xingliu, 2016/10/04 18:33:49]

Rename most of it, except the functions parameters in
RenderWidgetFeature::RenderWidgetFeatureDelegate.

Also added some comment of matching between document_id and render_widget_id.

[Khushal, 2016/10/04 18:49:54]

Sounds good. The RenderWidgetFeature should die once Helium steps in.

+
+  // The compositor instance.
+  std::unique_ptr<BlimpCompositor> compositor_;
+
+  // The BlimpDocumentManager that manages a list of BlimpDocuments, and holds
+  // a network message processor.
+  BlimpDocumentManager* manager_;

[Khushal, 2016/10/03 20:04:59]

You can just comment about why this is here, used to send messages to
corresponding render widget instance on the engine for this document.

[xingliu, 2016/10/04 18:33:49]

Done.

+
+  DISALLOW_COPY_AND_ASSIGN(BlimpDocument);
+};
+
+}  // namespace client
+}  // namespace blimp
+
+#endif  // BLIMP_CLIENT_CORE_RENDER_WIDGET_BLIMP_DOCUMENT_H_