Handle block helper functions in Breakpad symbol parser.  Block helper functions are associated with a source file but not associated with any line number.  For such functions, the Breakpad symbol file contains 0 for the line numbers.  Hence, 0 should be threated as valid line number.  For more information on block helper functions, please, take a look at http://clang.llvm.org/docs/Block-ABI-Apple.html.

Here is the symbol parser output:

E0906 11:27:06.051507 22535 basic_source_line_resolver.cc:76] Line 380187: ParseLine failed
E0906 11:27:06.051614 22535 basic_source_line_resolver.cc:76] Line 380188: ParseLine failed
E0906 11:27:06.051648 22535 basic_source_line_resolver.cc:76] Line 380190: ParseLine failed
E0906 11:27:06.051679 22535 basic_source_line_resolver.cc:76] Line 380191: ParseLine failed
E0906 11:27:06.200814 22535 basic_source_line_resolver.cc:76] Line 446729: ParseLine failed

Here are the contents of the Breakpad symbol file:

FUNC 440d60 49 0 __copy_helper_block_
440d60 b 0 3160    <<<-----------  the third number is the line number
440d6b 3e 0 3160    <<<----------------------------   same here
FUNC 440db0 36 0 __destroy_helper_block_
440db0 a 0 3160    <<<----------------------------   same here
440dba 2c 0 3160    <<<----------------------------   same here
Review URL: https://breakpad.appspot.com/629002

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1214 4c0a9323-5329-0410-9bdc-e9ce6186880e