Introduce the abstract class WebViewBase, to decouple WebViewImpl.

third_party/WebKit/Source/web/ExternalPopupMenu.cpp

Index: third_party/WebKit/Source/web/ExternalPopupMenu.cpp
diff --git a/third_party/WebKit/Source/web/ExternalPopupMenu.cpp b/third_party/WebKit/Source/web/ExternalPopupMenu.cpp
index a7fcdedf90111bacf8550cd1fc171b79205404e1..0df5cdd152221190c2c891cf7edcb0df80d275fa 100644
--- a/third_party/WebKit/Source/web/ExternalPopupMenu.cpp
+++ b/third_party/WebKit/Source/web/ExternalPopupMenu.cpp
@@ -43,20 +43,21 @@
 #include "platform/geometry/IntPoint.h"
 #include "platform/text/TextDirection.h"
 #include "platform/wtf/PtrUtil.h"
+#include "public/platform/WebCoalescedInputEvent.h"
 #include "public/platform/WebMouseEvent.h"
 #include "public/platform/WebVector.h"
 #include "public/web/WebExternalPopupMenu.h"
 #include "public/web/WebFrameClient.h"
 #include "public/web/WebMenuItemInfo.h"
 #include "public/web/WebPopupMenuInfo.h"
+#include "public/web/WebView.h"
 #include "web/WebLocalFrameImpl.h"
-#include "web/WebViewImpl.h"
 
 namespace blink {
 
 ExternalPopupMenu::ExternalPopupMenu(LocalFrame& frame,
                                      HTMLSelectElement& owner_element,
-                                     WebViewImpl& web_view)
+                                     WebView& web_view)
     : owner_element_(owner_element),
       local_frame_(frame),
       web_view_(web_view),