Break dependency on ChromeClientImpl for WebPluginContainerImpl.

third_party/WebKit/Source/core/page/ChromeClient.h

Index: third_party/WebKit/Source/core/page/ChromeClient.h
diff --git a/third_party/WebKit/Source/core/page/ChromeClient.h b/third_party/WebKit/Source/core/page/ChromeClient.h
index 8b07c8622ce2146ce72c200f4dd81d222fba86cc..1fd6e894944dc4367ea203e23dc84eab1a7cfcd6 100644
--- a/third_party/WebKit/Source/core/page/ChromeClient.h
+++ b/third_party/WebKit/Source/core/page/ChromeClient.h
@@ -88,6 +88,7 @@ struct CompositedSelection;
 struct DateTimeChooserParameters;
 struct FrameLoadRequest;
 struct ViewportDescription;
+struct WebCursorInfo;
 struct WebPoint;
 struct WebScreenInfo;
 struct WindowFeatures;
@@ -197,6 +198,8 @@ class CORE_EXPORT ChromeClient : public PlatformChromeClient {
     return last_mouse_over_node_.Get();
   }
 
+  virtual void SetCursorForPlugin(const WebCursorInfo&, LocalFrame*) = 0;
+
   // Returns a custom visible content rect if a viewport override is active.
   virtual WTF::Optional<IntRect> VisibleContentRectForPainting() const {
     return WTF::nullopt;