Add ExtendSelectionAndDelete handler in WebPlugin

Source/web/WebViewImpl.cpp

Index: Source/web/WebViewImpl.cpp
diff --git a/Source/web/WebViewImpl.cpp b/Source/web/WebViewImpl.cpp
index 2aa2f8c76b099732489994c76661023d14a81d16..2d0a147bad2700cf0e34d9b46cbec36c59838c09 100644
--- a/Source/web/WebViewImpl.cpp
+++ b/Source/web/WebViewImpl.cpp
@@ -2432,9 +2432,13 @@ WebVector<WebCompositionUnderline> WebViewImpl::compositionUnderlines() const
 
 void WebViewImpl::extendSelectionAndDelete(int before, int after)
 {
-    const Frame* focused = focusedWebCoreFrame();
+    Frame* focused = focusedWebCoreFrame();
     if (!focused)
         return;
+    if (WebPlugin* plugin = focusedPluginIfInputMethodSupported(focused)) {
+        plugin->extendSelectionAndDelete(before, after);
+        return;
+    }
     focused->inputMethodController().extendSelectionAndDelete(before, after);
 }