Add glue between the client and engine for Blimp

blimp/engine/browser/engine_render_widget_message_processor.h

Index: blimp/engine/browser/engine_render_widget_message_processor.h
diff --git a/blimp/engine/browser/engine_render_widget_message_processor.h b/blimp/engine/browser/engine_render_widget_message_processor.h
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+++ b/blimp/engine/browser/engine_render_widget_message_processor.h
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+// 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.
+
+#ifndef BLIMP_ENGINE_BROWSER_ENGINE_RENDER_WIDGET_MESSAGE_PROCESSOR_H_
+#define BLIMP_ENGINE_BROWSER_ENGINE_RENDER_WIDGET_MESSAGE_PROCESSOR_H_
+
+#include <vector>
+
+#include "base/containers/small_map.h"
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "blimp/net/blimp_message_processor.h"
+#include "blimp/net/input_message_processor.h"
+
+namespace blink {
+class WebInputEvent;
+}
+
+namespace blimp {
+
+// Handles all incoming and outgoing protobuf message types tied to a specific
+// RenderWidget. This includes BlimpMessage::INPUT, BlimpMessage::COMPOSITOR,
+// and BlimpMessage::RENDER_WIDGET messages.  Delegates can be added to be
+// notified of incoming messages. This class automatically handles dropping
+// stale BlimpMessage::RENDER_WIDGET messages from the client after a
+// RenderWidgetMessage::INITIALIZE message is sent.
+class EngineRenderWidgetMessageProcessor : public BlimpMessageProcessor {
+ public:
+  // A delegate to be notified of specific RenderWidget related incoming events.
+  class RenderWidgetMessageDelegate {
+   public:
+    // Called when the client is sending a WebInputEvent to the engine.
+    virtual void OnWebInputEvent(scoped_ptr<blink::WebInputEvent> event) = 0;
+
+    // Called when the client sent a CompositorMessage.  These messages should
+    // be sent to the engine's render process so they can be processed by the
+    // RemoteChannel of the compositor.
+    virtual void OnCompositorMessageReceived(
+        const std::vector<uint8_t>& message) = 0;
+  };
+
+  EngineRenderWidgetMessageProcessor(
+      BlimpMessageProcessor* render_widget_message_processor,
+      BlimpMessageProcessor* compositor_message_processor);
+  ~EngineRenderWidgetMessageProcessor() override;
+
+  // Notifies the client that the RenderWidget for a particular WebContents has
+  // changed.  When this is sent all incoming messages from the client sent
+  // before this message has been received will be dropped by this class.
+  void OnRenderWidgetInitialized(const int tab_id);
+
+  // Sends a CompositorMessage for |tab_id| to the client.
+  void SendCompositorMessage(const int tab_id,
+                             const std::vector<uint8_t>& message);
+
+  // Sets a RenderWidgetMessageDelegate to be notified of all incoming
+  // RenderWidget related messages for |tab_id| from the client.  There can only
+  // be one RenderWidgetMessageDelegate per tab.
+  void SetDelegate(const int tab_id, RenderWidgetMessageDelegate* delegate);
+  void RemoveDelegate(const int tab_id);
+
+  // BlimpMessageProcessor implementation.
+  void ProcessMessage(scoped_ptr<BlimpMessage> message,
+                      const net::CompletionCallback& callback) override;
+
+ private:
+  // Returns nullptr if no delegate is found.
+  RenderWidgetMessageDelegate* FindDelegate(const int tab_id);
+
+  // Returns 0 if no id is found.
+  uint32_t GetRenderWidgetId(const int tab_id);
+
+  typedef base::SmallMap<std::map<int, RenderWidgetMessageDelegate*> >
+      DelegateMap;
+  typedef base::SmallMap<std::map<int, uint32_t> > RenderWidgetIdMap;
+
+  DelegateMap delegates_;
+  RenderWidgetIdMap render_widget_ids_;
+
+  InputMessageProcessor input_message_processor_;
+
+  BlimpMessageProcessor* render_widget_message_processor_;
+  BlimpMessageProcessor* compositor_message_processor_;
+
+  DISALLOW_COPY_AND_ASSIGN(EngineRenderWidgetMessageProcessor);
+};
+
+}  // namespace blimp
+
+#endif  // BLIMP_ENGINE_BROWSER_ENGINE_RENDER_WIDGET_MESSAGE_PROCESSOR_H_