Remove FrameViewBase as base class of RemoteFrameView.

third_party/WebKit/Source/core/plugins/PluginView.h

Index: third_party/WebKit/Source/core/plugins/PluginView.h
diff --git a/third_party/WebKit/Source/core/plugins/PluginView.h b/third_party/WebKit/Source/core/plugins/PluginView.h
index e5ee0b32e333ffef9e160b82861484fe303cdb90..8bbd763f6757cf05eb0c070f451f8387bdf86af9 100644
--- a/third_party/WebKit/Source/core/plugins/PluginView.h
+++ b/third_party/WebKit/Source/core/plugins/PluginView.h
@@ -50,6 +50,8 @@ class CORE_EXPORT PluginView : public FrameOrPlugin {
  public:
   virtual ~PluginView() {}
 
+  bool IsPluginView() const override { return true; }
+
   virtual void SetParent(FrameView*) = 0;
   virtual FrameView* Parent() const = 0;
   virtual void SetParentVisible(bool) = 0;
@@ -76,6 +78,12 @@ class CORE_EXPORT PluginView : public FrameOrPlugin {
   virtual void InvalidatePaintIfNeeded() {}
 };
 
+DEFINE_TYPE_CASTS(PluginView,
+                  FrameOrPlugin,
+                  frame_or_plugin,
+                  frame_or_plugin->IsPluginView(),
+                  frame_or_plugin.IsPluginView());
+
 }  // namespace blink
 
 #endif  // PluginView_h