Match 'i' attribute selector modifier case-insensitively

third_party/WebKit/Source/core/css/parser/CSSSelectorParser.cpp

Index: third_party/WebKit/Source/core/css/parser/CSSSelectorParser.cpp
diff --git a/third_party/WebKit/Source/core/css/parser/CSSSelectorParser.cpp b/third_party/WebKit/Source/core/css/parser/CSSSelectorParser.cpp
index be1b17a26a02cabb1a8b16428e29047761661e2a..84ba8d672eb9deb3281d3b7e2420354597e69b32 100644
--- a/third_party/WebKit/Source/core/css/parser/CSSSelectorParser.cpp
+++ b/third_party/WebKit/Source/core/css/parser/CSSSelectorParser.cpp
@@ -608,7 +608,7 @@ CSSSelector::AttributeMatchType CSSSelectorParser::consumeAttributeFlags(CSSPars
     if (range.peek().type() != IdentToken)
         return CSSSelector::CaseSensitive;
     const CSSParserToken& flag = range.consumeIncludingWhitespace();
-    if (String(flag.value()) == "i")
+    if (flag.valueEqualsIgnoringASCIICase("i"))

[rune, 2016/01/22 21:48:01]

Briefly looking through the relevant specs, it seems every keyword is supposed
to be matched ascii-case-insensitively. Looking at the use of
valueEqualsIgnoringCase/equalsIgnoringCase, it seems it should always have been
valueEqualsIgnoringASCIICase/equalsIgnoringASCIICase.

If so, could we just get rid of the unicode-case-insensitive matching functions?

[fs, 2016/01/22 23:53:17]

I was hoping we could. I was planning on doing that in follow-up CLs (want this
as pristine as possible since I want to try to merge it to M49) - not looking
forward to chasing testcases for all uses though, so hopefully we can punt on
those a bit... (else I'll need to read the case-folding tables very
thoroughly...)

[rune, 2016/01/24 10:46:26]

In another context I was trying to find out if we case folding were we'd make
'i' 'I' case-equal to some other character, and couldn't. Maybe you could just
use valueEqualsIgnoringCase for this CL instead?

[fs, 2016/01/25 09:47:19]

If you look at the TC I added, you'll see one example of a non-ascii char that
maps to lower-case ('i') and one that maps to upper-case ('I'):

http://www.fileformat.info/info/unicode/char/0130/index.htm
http://www.fileformat.info/info/unicode/char/0131/index.htm

I did consider just using valueEqualsIgnoringCase "for now" though since that
would mean a trivial backport (merge). This is not that much larger though, so
it felt reasonable to "set the example" =). (Also, you newer know what level of
picky reviewers will choose ;-))

[rune, 2016/01/25 10:15:29]

I ran your new cases locally, and those test pass with valueEqualsIgnoringCase.
We do a simpler for of folding than what's required to make those fail, I think.

[fs, 2016/01/25 11:30:31]

Ok, so looks like it pans out fine in these cases, so I guess we can run with
scissors for a while longer.

         return CSSSelector::CaseInsensitive;
     m_failedParsing = true;
     return CSSSelector::CaseSensitive;