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 70c49355e72341102a828fce9a451c12ce341078..aa57ca011d3dd3e8d397d6396fd4a8f118c75010 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;
@@ -77,6 +79,12 @@ class CORE_EXPORT PluginView : public FrameOrPlugin {
   virtual void InvalidatePaint() {}
 };
 
+DEFINE_TYPE_CASTS(PluginView,
+                  FrameOrPlugin,
+                  frame_or_plugin,
+                  frame_or_plugin->IsPluginView(),
+                  frame_or_plugin.IsPluginView());
+
 }  // namespace blink
 
 #endif  // PluginView_h