Add trim, trimLeft and trimRight methods to String

Based on a recent patch for Webkit. 
trim is defined in ES 5 section 15.5.4.20.

BUG=465

[Christian Plesner Hansen, 2009-10-12 15:14:29]

I would suggest using two bools instead of encoding the left/right values into a
bool.  Otherwise lgtm.

http://codereview.chromium.org/266050/diff/4001/4003
File src/runtime.cc (right):

http://codereview.chromium.org/266050/diff/4001/4003#newcode3596
Line 3596: CONVERT_CHECKED(Smi, trimKind, args[1]);
Using two boolean arguments instead of encoding the value into an integer would
simplify the code.

[Christian Plesner Hansen, 2009-10-12 15:15:09]

> [...] instead of encoding the left/right values into a bool.  

That should have been "into an int".

[Jan de Mooij, 2009-10-12 15:34:11]

On 2009/10/12 15:15:09, Christian Plesner Hansen wrote:
> > [...] instead of encoding the left/right values into a bool.  
> 
> That should have been "into an int".

Agreed. See updated patch.

[Christian Plesner Hansen, 2009-10-12 17:57:43]

Lgtm.  I'll land this tomorrow.

[Erik Corry, 2009-10-12 18:51:56]

LGTM - thanks for the patch.

http://codereview.chromium.org/266050/diff/5002/6002
File src/runtime.cc (right):

http://codereview.chromium.org/266050/diff/5002/6002#newcode3610
Line 3610: while (right > left && IsTrimWhiteSpace(s->Get(right-1)))
Please add spaces around '-' and braces around multi-line if statement body.

http://codereview.chromium.org/266050/diff/5002/6001
File test/mjsunit/third_party/string-trim.js (right):

http://codereview.chromium.org/266050/diff/5002/6001#newcode32
Line 32: // Based on LayoutTests/fast/js/script-tests/string-trim.js
I think the test files should conform to the formatting guidelines too, in which
case in this file the comments need to be reformatted so they are within 80
characters, start with a capital letter and end with a full stop and have at
least two spaces before and one space after the //.  Also indentation should be
two characters.

[Jan de Mooij, 2009-10-12 21:04:48]

Thanks for your comments.

I am not sure though what you mean by "two spaces before [..] the //". Let me
know if there is still something wrong.

[Christian Plesner Hansen, 2009-10-13 08:15:50]

Landed in http://code.google.com/p/v8/source/detail?r=3052 (I fixed Erik's last
comments on landing).

[Erik Corry, 2009-10-13 08:27:43]

http://codereview.chromium.org/266050/diff/8001/7002
File test/mjsunit/third_party/string-trim.js (right):

http://codereview.chromium.org/266050/diff/8001/7002#newcode81
Line 81: rightTrimString = wsString   + testString; // Trimmed from the right.
You 'need' an extra space immediately preceding the double slash (//) here.

http://codereview.chromium.org/266050/diff/8001/7002#newcode99
Line 99: var testValues = [0, Infinity, NaN, true, false, ({}), ['an','array']
Is there a missing comma at the end of this line?  I can't quite parse this, but
perhaps the machine can :-).