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1 // Copyright 2015 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #ifndef WebFrameImplBase_h | |
6 #define WebFrameImplBase_h | |
7 | |
8 #include "platform/heap/Handle.h" | |
9 #include "platform/wtf/text/AtomicString.h" | |
10 #include "web/WebExport.h" | |
11 | |
12 namespace blink { | |
13 | |
14 class Frame; | |
15 class FrameOwner; | |
16 class Page; | |
17 | |
18 // WebFrameImplBase exists to avoid the diamond inheritance problem: | |
19 // - The public interfaces WebLocalFrame/WebRemoteFrame extend WebFrame. | |
20 // - WebLocalFrameImpl implements WebLocalFrame and WebRemoteFrameImpl | |
21 // implements WebRemoteFrame. | |
22 // - The private implementations should share some functionality, but cannot | |
23 // inherit from a common base class inheriting WebFrame. This would result in | |
24 // WebFrame beind inherited from two different base classes. | |
25 // | |
26 // To get around this, only the private implementations have WebFrameImplBase as | |
27 // a base class. WebFrame exposes a virtual accessor to retrieve the underlying | |
28 // implementation as an instance of the base class, but has no inheritance | |
29 // relationship with it. The cost is a virtual indirection, but this is nicer | |
30 // than the previous manual dispatch emulating real virtual dispatch. | |
31 class WEB_EXPORT WebFrameImplBase | |
32 : public GarbageCollectedFinalized<WebFrameImplBase> { | |
33 public: | |
34 virtual ~WebFrameImplBase(); | |
35 | |
36 virtual void InitializeCoreFrame(Page&, | |
37 FrameOwner*, | |
38 const AtomicString& name) = 0; | |
39 // TODO(dcheng): Rename this to coreFrame()? This probably also shouldn't be | |
40 // const... | |
41 virtual Frame* GetFrame() const = 0; | |
42 | |
43 DECLARE_VIRTUAL_TRACE(); | |
44 }; | |
45 | |
46 } // namespace blink | |
47 | |
48 #endif // WebFrameImplBase_h | |
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