Allow Minidump class to be instantiated with stream instead of file

We'd like to be able to process minidump data that's present in memory instead
of on disk. I've refactored the Minidump class slightly to allow a std::istream
to be passed in in the constructor instead of just a file. I added a very basic
minidump_unittest to ensure that reading from a file or from a std::stringstream
works.

Mark, can you take a look at this patch?

[Mark Mentovai]

http://breakpad.appspot.com/46001/diff/1/6
File Makefile.am (right):

http://breakpad.appspot.com/46001/diff/1/6#newcode117
Line 117: src/processor/minidump_unittest \
sort: _u follows _s.

http://breakpad.appspot.com/46001/diff/1/6#newcode155
Line 155: src_processor_minidump_unittest_SOURCES = \
This block should be moved so that the blocks remain sorted too.

http://breakpad.appspot.com/46001/diff/1/2
File Makefile.in (right):

http://breakpad.appspot.com/46001/diff/1/2#newcode1
Line 1: # Makefile.in generated by automake 1.10 from Makefile.am.
Regenerate after revising Makefile.am.

http://breakpad.appspot.com/46001/diff/1/4
File src/processor/minidump.cc (left):

http://breakpad.appspot.com/46001/diff/1/4#oldcode3621
Line 3621: // depends on is mFD, and an unset or invalid fd may generate an
mFD, hah, wow, that's real old.

http://breakpad.appspot.com/46001/diff/1/4
File src/processor/minidump.cc (right):

http://breakpad.appspot.com/46001/diff/1/4#newcode3347
Line 3347: path_(""),
Use path_() here.  The default constructor gives you an empty string.

http://breakpad.appspot.com/46001/diff/1/4#newcode3348
Line 3348: stream_(&stream),
Hmm.

I guess you should document in the header that for this constructor, Minidump
holds a weak pointer to the stream, and the caller must ensure that the stream
is valid as long as the Minidump object is.

http://breakpad.appspot.com/46001/diff/1/4#newcode3357
Line 3357: if (!path_.empty())
I think this file always uses {} on conditionals, even on single-line ones.  You
certainly used {} on the one immediately preceding this one.

http://breakpad.appspot.com/46001/diff/1/4#newcode3633
Line 3633: if (!stream_)
{}

http://breakpad.appspot.com/46001/diff/1/4#newcode3654
Line 3654: if (!stream_)
{}

http://breakpad.appspot.com/46001/diff/1/3
File src/processor/minidump_unittest.cc (right):

http://breakpad.appspot.com/46001/diff/1/3#newcode34
Line 34: #include <string>
sort

http://breakpad.appspot.com/46001/diff/1/3#newcode97
Line 97: }  // namespace
Blank line before.

http://breakpad.appspot.com/46001/diff/1/3#newcode99
Line 99: int main(int argc, char *argv[]) {
The rest of this file puts the * on the type.

[Ted Mielczarek]

Committed in r438.