Remove code that adds "Url Protocol" key to registry entry...

Remove code that adds "Url Protocol" key to registry entry
for ChromeHTML.  This removes the feature where you
can launch Chrome using chromehtml: links in e.g. IE.

BUG=5825
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=10357

[Sverrir, 2009-02-18 22:03:11]

Remove the "URL Protocol" Value from registry.  This is not required for file
registration and having this means it means that chrome can be launched from
e.g. a web page which is not what we want.

[kuchhal, 2009-02-18 22:28:22]

I dont think we can remove URL Protocol key. See -
http://src.chromium.org/viewvc/chrome?view=rev&revision=6376

[Sverrir, 2009-02-18 22:52:13]

But they would not be looking under ChromeHTML but under http - right? 
We do not want to support chromehtml:foo URL's, only http:foo

[SkyLined, 2009-02-25 20:42:28]

This does not actually seem to remove the value: this removes the code that adds
it during installation but everyone that already has Chrome installed will
continue to have this feature.

[Sverrir, 2009-02-25 21:51:00]

The RemoveUrlProtocol() is meant to remove the key - both for HKLM and HKCU.

[SkyLined, 2009-02-26 09:07:43]

I see, I missed that earlier, sorry. What happens if the call fail, eg. when the
process is not elevated?

[Sverrir, 2009-02-27 19:11:36]

I have another change pending that fixes that.  I was waiting for more feedback
on it but I guess its OK to check in as well.
See: http://codereview.chromium.org/20469/show