Source/core/frame/FrameHost.h

/*
 * Copyright (C) 2013 Google Inc. All rights reserved.
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#ifndef FrameHost_h
#define FrameHost_h

#include "core/frame/PinchViewport.h"
#include "platform/heap/Handle.h"
#include "wtf/FastAllocBase.h"
#include "wtf/Noncopyable.h"
#include "wtf/OwnPtr.h"
#include "wtf/PassOwnPtr.h"

namespace WebCore {

class Chrome;
class EventHandlerRegistry;
class Page;
class PinchViewport;
class Settings;
class UseCounter;
class Visitor;

// FrameHost is the set of global data shared between multiple frames
// and is provided by the embedder to each frame when created.
// FrameHost currently corresponds to the Page object in core/page
// however the concept of a Page is moving up out of Blink.
// In an out-of-process iframe world, a single Page may have
// multiple frames in different process, thus Page becomes a
// browser-level concept and Blink core/ only knows about its LocalFrame (and FrameHost).
// Separating Page from the rest of core/ through this indirection
// allows us to slowly refactor Page without breaking the rest of core.
class FrameHost FINAL : public NoBaseWillBeGarbageCollectedFinalized<FrameHost> {
    WTF_MAKE_NONCOPYABLE(FrameHost); WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED;
public:
    static PassOwnPtrWillBeRawPtr<FrameHost> create(Page&);
    ~FrameHost();

    // Careful: This function will eventually be removed.
    Page& page() const { return *m_page; }
    Settings& settings() const;
    Chrome& chrome() const;
    UseCounter& useCounter() const;

    // Corresponds to pixel density of the device where this Page is
    // being displayed. In multi-monitor setups this can vary between pages.
    // This value does not account for Page zoom, use LocalFrame::devicePixelRatio instead.
    float deviceScaleFactor() const;

    PinchViewport& pinchViewport() const;
    EventHandlerRegistry& eventHandlerRegistry() const;

    void trace(Visitor*);

private:
    explicit FrameHost(Page&);

    RawPtrWillBeMember<Page> m_page;
    const OwnPtr<PinchViewport> m_pinchViewport;
    const OwnPtrWillBeMember<EventHandlerRegistry> m_eventHandlerRegistry;
};

}

#endif // FrameHost_h