Implement unregisterProtocolHandler() function on CUSTOM_SCHEME_HANDLER

Source/web/ChromeClientImpl.h

Index: Source/web/ChromeClientImpl.h
diff --git a/Source/web/ChromeClientImpl.h b/Source/web/ChromeClientImpl.h
index d315694e59bb77ceb98c40536ad8d344b6a0869a..7823bb3d8277919a6cc31f9365f82e67553f7d19 100644
--- a/Source/web/ChromeClientImpl.h
+++ b/Source/web/ChromeClientImpl.h
@@ -208,6 +208,10 @@ public:
     ~NavigatorContentUtilsClientImpl() { }
 
     virtual void registerProtocolHandler(const String& scheme, const String& baseURL, const String& url, const String& title) OVERRIDE;
+#if ENABLE(CUSTOM_SCHEME_HANDLER)

[abarth-chromium, 2013/08/21 17:10:19]

Please do not add any more ENABLE #if statements to the code base.  Using a
runtime enabled flag in the IDL is great and all you need here.

The way I would approach this change is to first remove
ENABLE(CUSTOM_SCHEME_HANDLER) entirely in favor of a runtime flag.  Then I would
add the new functionality.

[gyuyoung-inactive, 2013/08/22 01:12:38]

Abarth, I upload a patch to remove all ENABLE(CUSTOM_SCHEME_HANDLER) at
https://codereview.chromium.org/22859043/. I will update this patch after
landing it. Thanks.

+    virtual CustomHandlersState isProtocolHandlerRegistered(const String& scheme, const String& baseURL, const String& url) OVERRIDE;
+    virtual void unregisterProtocolHandler(const String& scheme, const String& baseURL, const String& url) OVERRIDE;
+#endif
 
 private:
     explicit NavigatorContentUtilsClientImpl(WebViewImpl*);