content/browser/frame_host/cross_process_frame_connector.h

// 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.

#ifndef CONTENT_BROWSER_FRAME_HOST_CROSS_PROCESS_FRAME_CONNECTOR_H_
#define CONTENT_BROWSER_FRAME_HOST_CROSS_PROCESS_FRAME_CONNECTOR_H_

#include <stdint.h>

#include "cc/output/compositor_frame.h"
#include "content/common/content_export.h"
#include "ui/gfx/geometry/rect.h"

namespace blink {
class WebInputEvent;
struct WebScreenInfo;
}

namespace cc {
struct SurfaceId;
struct SurfaceSequence;
}

namespace IPC {
class Message;
}

struct FrameHostMsg_CompositorFrameSwappedACK_Params;
struct FrameHostMsg_ReclaimCompositorResources_Params;

namespace content {
class RenderFrameProxyHost;
class RenderWidgetHostImpl;
class RenderWidgetHostViewBase;
class RenderWidgetHostViewChildFrame;
class WebCursor;

// CrossProcessFrameConnector provides the platform view abstraction for
// RenderWidgetHostViewChildFrame allowing RWHVChildFrame to remain ignorant
// of RenderFrameHost.
//
// The RenderWidgetHostView of an out-of-process child frame needs to
// communicate with the RenderFrameProxyHost representing this frame in the
// process of the parent frame. For example, assume you have this page:
//
//   -----------------
//   | frame 1       |
//   |  -----------  |
//   |  | frame 2 |  |
//   |  -----------  |
//   -----------------
//
// If frames 1 and 2 are in process A and B, there are 4 RenderFrameHosts:
//   A1 - RFH for frame 1 in process A
//   B1 - RFPH for frame 1 in process B
//   A2 - RFPH for frame 2 in process A
//   B2 - RFH for frame 2 in process B
//
// B2, having a parent frame in a different process, will have a
// RenderWidgetHostViewChildFrame. This RenderWidgetHostViewChildFrame needs
// to communicate with A2 because the embedding process is an abstract
// for the child frame -- it needs information necessary for compositing child
// frame textures, and also can pass platform messages such as view resizing.
// CrossProcessFrameConnector bridges between B2's
// RenderWidgetHostViewChildFrame and A2 to allow for this communication.
// (Note: B1 is only mentioned for completeness. It is not needed in this
// example.)
//
// CrossProcessFrameConnector objects are owned by the RenderFrameProxyHost
// in the child frame's RenderFrameHostManager corresponding to the parent's
// SiteInstance, A2 in the picture above. When a child frame navigates in a new
// process, set_view() is called to update to the new view.
//
class CONTENT_EXPORT CrossProcessFrameConnector {
 public:
  // |frame_proxy_in_parent_renderer| corresponds to A2 in the example above.
  explicit CrossProcessFrameConnector(
      RenderFrameProxyHost* frame_proxy_in_parent_renderer);
  virtual ~CrossProcessFrameConnector();

  bool OnMessageReceived(const IPC::Message &msg);

  // |view| corresponds to B2's RenderWidgetHostViewChildFrame in the example
  // above.
  void set_view(RenderWidgetHostViewChildFrame* view);
  RenderWidgetHostViewChildFrame* get_view_for_testing() { return view_; }

  void RenderProcessGone();

  virtual void ChildFrameCompositorFrameSwapped(
      uint32_t output_surface_id,
      int host_id,
      int route_id,
      scoped_ptr<cc::CompositorFrame> frame);
  virtual void SetChildFrameSurface(const cc::SurfaceId& surface_id,
                                    const gfx::Size& frame_size,
                                    float scale_factor,
                                    const cc::SurfaceSequence& sequence);

  gfx::Rect ChildFrameRect();
  float device_scale_factor() const { return device_scale_factor_; }
  void GetScreenInfo(blink::WebScreenInfo* results);
  void UpdateCursor(const WebCursor& cursor);
  void TransformPointToRootCoordSpace(const gfx::Point& point,
                                      cc::SurfaceId surface_id,
                                      gfx::Point* transformed_point);

  // Determines whether the root RenderWidgetHostView (and thus the current
  // page) has focus.
  bool HasFocus();

 private:
  // Handlers for messages received from the parent frame.
  void OnCompositorFrameSwappedACK(
      const FrameHostMsg_CompositorFrameSwappedACK_Params& params);
  void OnReclaimCompositorResources(
      const FrameHostMsg_ReclaimCompositorResources_Params& params);
  void OnForwardInputEvent(const blink::WebInputEvent* event);
  void OnFrameRectChanged(const gfx::Rect& frame_rect);
  void OnVisibilityChanged(bool visible);
  void OnInitializeChildFrame(gfx::Rect frame_rect, float scale_factor);
  void OnSatisfySequence(const cc::SurfaceSequence& sequence);
  void OnRequireSequence(const cc::SurfaceId& id,
                         const cc::SurfaceSequence& sequence);

  void SetDeviceScaleFactor(float scale_factor);
  void SetSize(gfx::Rect frame_rect);

  // Retrieve the view for the top-level frame under the same WebContents.
  RenderWidgetHostViewBase* GetRootRenderWidgetHostView();

  // The RenderFrameProxyHost that routes messages to the parent frame's
  // renderer process.
  RenderFrameProxyHost* frame_proxy_in_parent_renderer_;

  // The RenderWidgetHostView for the frame. Initially NULL.
  RenderWidgetHostViewChildFrame* view_;

  gfx::Rect child_frame_rect_;
  float device_scale_factor_;
};

}  // namespace content

#endif  // CONTENT_BROWSER_FRAME_HOST_CROSS_PROCESS_FRAME_CONNECTOR_H_