Cleanup: Add more conversion helpers for usage.

Source/web/WebPopupMenuImpl.h

Index: Source/web/WebPopupMenuImpl.h
diff --git a/Source/web/WebPopupMenuImpl.h b/Source/web/WebPopupMenuImpl.h
index f2decbb1b550a02fc0a1caf7e14b6504752a3931..dc2db53ca0c37378901c5280217ff6241b349a6e 100644
--- a/Source/web/WebPopupMenuImpl.h
+++ b/Source/web/WebPopupMenuImpl.h
@@ -86,6 +86,7 @@ public:
     virtual bool caretOrSelectionRange(size_t* location, size_t* length) OVERRIDE;
     virtual void setTextDirection(WebTextDirection) OVERRIDE;
     virtual bool isAcceleratedCompositingActive() const OVERRIDE { return false; }
+    virtual bool isPagePopup() const OVERRIDE { return true; }
 
     // WebPopupMenuImpl
     void initialize(WebCore::FramelessScrollView* widget, const WebRect& bounds);
@@ -134,6 +135,20 @@ public:
     WebCore::FramelessScrollView* m_widget;
 };
 
+inline WebPopupMenuImpl* toWebPopupMenuImpl(WebWidget* widget)
+{
+    ASSERT_WITH_SECURITY_IMPLICATION(widget && widget->isPagePopup());

[tkent, 2013/10/08 05:24:04]

should accept null widget for consistency.

+    return static_cast<WebPopupMenuImpl*>(widget);
+}
+
+inline WebPopupMenuImpl* toWebPopupMenuImpl(WebCore::FramelessScrollViewClient* client)
+{
+    // We need not check for type of FramelessScrollViewClient, since WebPopupMenuImpl
+    // is the only derived class from FramelessScrollViewClient.
+    ASSERT_WITH_SECURITY_IMPLICATION(client);

[tkent, 2013/10/08 05:24:04]

null pointer has no security implication.
should accept null client for consistency.

+    return static_cast<WebPopupMenuImpl*>(client);
+}
+
 } // namespace WebKit
 
 #endif