base::HexStringToInt conversion function treats the string "0x" as a valid hex number

Fixes a corner case bug in the HexStringToInt conversion function which caused the string "0x" to be treated as a valid hexadecimal number.
Although the parsed result was 0, the boolean flag returned indicated that the hex number was in proper format

The IteratorRangeToNumber class's Invoke function increments the string pointer by 2 if the string starts with "0x" or "0X" and the length is greater than *or equal* to 2
If the length of the string is 2, i.e "0x", after the pointer increment, the string would be empty and the function returns true as the parse result

Changed the condition from "greater than or equal to" to "greater than"

Added another test cases which now properly treats "0x" as an invalid hex string

Contributed by ali.akbar@gmail.com

BUG=92054
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=96605

[erikwright (departed), 2011-08-08 17:48:51]

LGTM.

[ali.akbar_gmail.com, 2011-08-08 19:27:25]

On 2011/08/08 17:48:51, erikwright wrote:
> LGTM.

Erik, Thank you for reviewing the patch.  As per the doc, I have added
"Contributed by" clause in the description. 

Also, this is my first patch, so I have signed the CLA

If everything looks good, could you commit the changes?

Thanks

[ali.akbar_gmail.com, 2011-08-09 07:16:36]

Erik,  Could you pass this patch on to the try server?

Thanks.

[erikwright (departed), 2011-08-10 18:48:52]

On 2011/08/09 07:16:36, Ali Akbar wrote:
> Erik,  Could you pass this patch on to the try server?
> 
> Thanks.

Hi Ali,

I have submitted a try job. It appears there are some SVN issues that may or may
not affect try jobs. If necessary I'll resubmit later.

In the meantime, please add your name to AUTHORS as part of this CL.

You will also need a review from someone in
http://src.chromium.org/viewvc/chrome/trunk/src/base/OWNERS?revision=81630&vi...
. I'm adding mark@ for the moment.

When you have submitted the patch to AUTHORS, the try job passes, and you have
owner's LGTM, the CL may be committed.

Thanks for contributing to Chromium,

Erik

[Mark Mentovai, 2011-08-12 17:44:00]

LGTM both for purposes of review and OWNERS approval.

[commit-bot: I haz the power, 2011-08-12 20:13:23]

Change committed as 96605

[ali.akbar_gmail.com, 2011-08-12 20:17:56]

On 2011/08/12 17:44:00, Mark Mentovai wrote:
> LGTM both for purposes of review and OWNERS approval.

Hi Mark / Erik,
  Thanks for the review

Ali