RemoteBridgeFrameOwner: keep better track of the attached frame

third_party/WebKit/Source/core/frame/FrameOwner.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 FrameOwner_h
 #define FrameOwner_h
 
 #include "core/CoreExport.h"
 #include "core/dom/SandboxFlags.h"
 #include "platform/heap/Handle.h"
 #include "platform/scroll/ScrollTypes.h"
 
 namespace blink {
 
+class Frame;
+
 // Oilpan: all FrameOwner instances are GCed objects. FrameOwner additionally
 // derives from GarbageCollectedMixin so that Member<FrameOwner> references can
 // be kept (e.g., Frame::m_owner.)
 class CORE_EXPORT FrameOwner : public WillBeGarbageCollectedMixin {
 public:
     virtual ~FrameOwner() { }
     DEFINE_INLINE_VIRTUAL_TRACE() { }
 
     virtual bool isLocal() const = 0;
 
+    virtual void setContentFrame(Frame&) = 0;
+    virtual void clearContentFrame() = 0;
+
     virtual SandboxFlags getSandboxFlags() const = 0;
     virtual void dispatchLoad() = 0;
 
     // On load failure, a frame can ask its owner to render fallback content
     // which replaces the frame contents.
     virtual void renderFallbackContent() = 0;
 
     virtual ScrollbarMode scrollingMode() const = 0;
     virtual int marginWidth() const = 0;
     virtual int marginHeight() const = 0;
 };
 
+class CORE_EXPORT DummyFrameOwner : public NoBaseWillBeGarbageCollectedFinalized<DummyFrameOwner>, public FrameOwner {
+    WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(DummyFrameOwner);
+public:
+    static PassOwnPtrWillBeRawPtr<DummyFrameOwner> create()
+    {
+        return adoptPtrWillBeNoop(new DummyFrameOwner);
+    }
+
+    DEFINE_INLINE_VIRTUAL_TRACE() { FrameOwner::trace(visitor); }
+
+    // FrameOwner overrides:
+    bool isLocal() const override { return false; }
+    void setContentFrame(Frame&) override { }
+    void clearContentFrame() override { }
+    SandboxFlags getSandboxFlags() const override { return SandboxNone; }
+    void dispatchLoad() override { }
+    void renderFallbackContent() override { }
+    ScrollbarMode scrollingMode() const override { return ScrollbarAuto; }
+    int marginWidth() const override { return -1; }
+    int marginHeight() const override { return -1; }
+};
+
 } // namespace blink
 
 #endif // FrameOwner_h