Remove unused code, improve speed of Parser::CurrentToken (improvement seen in measurements and pro…

Remove unused code, improve speed of Parser::CurrentToken (improvement seen in measurements and profile).

R=hausner@google.com

Committed: https://code.google.com/p/dart/source/detail?r=36710

[hausner, 2014-05-27 21:03:29]

The change looks technically correct, so LGTM.

But I think it's not the right thing to do since performance is even more at the
whim of inlining. See comment below.

(Also, if we really want to do something about parsing performance, let's change
the language so less lookahead is necessary.)

https://codereview.chromium.org/293403009/diff/1/runtime/vm/parser.h
File runtime/vm/parser.h (right):

https://codereview.chromium.org/293403009/diff/1/runtime/vm/parser.h#newcode244
runtime/vm/parser.h:244: Token::Kind CurrentToken() {
The performance now depends even more on the whim of the compiler's inlining
magic. In most cases, we only call CurrentToken() once to determine what we are
parsing. In cases where the parser calls it repetitively without advancing, we
should cache it locally. Eg. in ParseStatement() or ParsePrimary().

[srdjan, 2014-05-27 21:12:33]

Committed patchset #1 manually as r36710 (presubmit successful).