Introduce WebPluginContainerBase to abstract WebPluginContainerImpl.

third_party/WebKit/Source/core/exported/WebPluginContainerBase.h

+// Copyright 2017 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 WebViewBase_h
+
+#ifndef WebPluginContainerBase_h
+#define WebPluginContainerBase_h
+
+#include "core/CoreExport.h"
+#include "core/dom/ContextLifecycleObserver.h"
+#include "core/plugins/PluginView.h"
+#include "public/web/WebPluginContainer.h"
+
+namespace blink {
+
+class ResourceError;
+
+struct WebPrintParams;
+struct WebPrintPresetOptions;
+
+// WebPluginContainerBase is a temporary class the provides a layer of
+// abstraction for WebPluginContainerImpl. Mehtods that are declared public in
+// WebPluginContainerImpl that are not overrides from PluginView,
+// WebPuglinContainer or ContextClient will be declared pure virtual in
+// WebPluginContainerBase. Classes that then have a dependency on
+// WebPluginContainerImpl will then take a dependency on WebPluginContainerBase
+// instead, so we can remove cyclic dependencies in web/ and move classes from
+// web/ into core/ or modules.
+// TODO(slangley): Remove this class once WebPluginContainerImpl is in core/.
+class CORE_EXPORT WebPluginContainerBase
+    : public GarbageCollectedFinalized<WebPluginContainerBase>,
+      public PluginView,
+      NON_EXPORTED_BASE(public WebPluginContainer),
+      public ContextClient {
+  USING_GARBAGE_COLLECTED_MIXIN(WebPluginContainerBase);
+  USING_PRE_FINALIZER(WebPluginContainerBase, DispatchDispose);
+
+ public:
+  virtual int PrintBegin(const WebPrintParams&) const = 0;
+  virtual void PrintPage(int page_number, GraphicsContext&, const IntRect&) = 0;
+  virtual void PrintEnd() = 0;
+  virtual bool ExecuteEditCommand(const WebString& name) = 0;
+  virtual bool ExecuteEditCommand(const WebString& name,
+                                  const WebString& value) = 0;
+  virtual bool SupportsPaginatedPrint() const = 0;
+  virtual bool IsPrintScalingDisabled() const = 0;
+  virtual bool GetPrintPresetOptionsFromDocument(
+      WebPrintPresetOptions*) const = 0;
+  virtual void DidFinishLoading() = 0;
+  virtual void DidFailLoading(const ResourceError&) = 0;
+  virtual void CalculateGeometry(IntRect& window_rect,
+                                 IntRect& clip_rect,
+                                 IntRect& unobscured_rect) = 0;
+
+  DECLARE_VIRTUAL_TRACE();
+  // USING_PRE_FINALIZER does not allow for virtual dispatch from the finalizer
+  // method. Here we call Dispose() which does the correct virtual dispatch.
+  void DispatchDispose() { Dispose(); }

[haraken, 2017/05/19 07:44:15]

This is confusing. Can we do something like:

- Move USING_PRE_FINALIZER to WebPluginContainerImpl.
- Make the pre-finalizer call WebPluginContainerImpl::PreFinalize (a non-virtual
method).
- Make WebPluginContainerImpl::PreFinalize call Dispose.

However, why do we need the pre-finalilzer in the first place? It looks weird
that there is no explicit timing to dispose the WebPluginContainerImpl.

+
+ protected:
+  explicit WebPluginContainerBase(LocalFrame*);
+};
+
+DEFINE_TYPE_CASTS(WebPluginContainerBase,
+                  PluginView,
+                  plugin,
+                  plugin->IsPluginContainer(),
+                  plugin.IsPluginContainer());
+// Unlike FrameViewBase, we need not worry about object type for container.
+// WebPluginContainerBase is the only subclass of WebPluginContainer.
+DEFINE_TYPE_CASTS(WebPluginContainerBase,
+                  WebPluginContainer,
+                  container,
+                  true,
+                  true);
+
+}  // nammespace blink
+
+#endif  // WebPluginContainerBase_h