Question: I need to inspect javascript execution (webview widget) in an android application,
 while debugging; through SDK & usb cable and/or http/websockets;
 from destop computer (e.g. chrome running on desktop).

Webkit's sources includes DebuggerServer implementation
 ( platform\_external\_webkit\Source\WebKit\android\wds\DebugServer.cpp )
 accessible at cpp level, and bound if flag WDS is enabled (at build time?)

Source\WebKit\android\jni\WebCoreFrameBridge.cpp:#if ENABLE(WDS)
Source\WebKit\android\jni\WebCoreFrameBridge.cpp: WDS::server()->addFrame(frame);

The default port for server is 9999

The sources show that all is implemented (at Cpp level) to enable the feature,
 but I have not found any reference searching the web for experiences
 using live debugging at javascript level in adroid devices automating
 webkit's inspector interface.

1.- Are the feature present, in binary form, executing in actual android devices?
 (has adroid's distribution of webkit been built without WDS flag enabled? :-( )

2.- Can the remote debug feature be enabled/used from javascript or application
 (at java level) e.g. at startup of app?

3.- In case it is possible to enable the webkit inspector/debugger feature,
 how to make it possible to interact from remote application ? (e.g. from
 another javascript app using websockets, or chrome on desktop computers).

Some paragraphs explaining the mechanics like
 <https://developers.google.com/chrome-developer-tools/docs/remote-debugging#remote>
 would be nice!

thanks in advance for any information, or references about this topic.
I consider important to enable remote debugging (in the device) at
 javascript level to make it possible modern development of HTML5
 applications and happy debugging experience.

cheers,
Ale.

Answer: 
Now it is easy with Android 4.4. See <https://developers.google.com/chrome-developer-tools/docs/remote-debugging#debugging-webviews>
It cannot be done, because the debugger backend code is not there. The source code you are referencing to is a copy of webkit source in android, but it is not compiled into android release bits.