Fix disabled InstallerStateTest.RemoveOldVersionDirs on x64

Fix InstallerStateTest.RemoveOldVersionDirs by fixing the comparison in alternate_version_generator.cc to use max(DWORD) rather than max(size_t) since CreateFileMapping takes a DWORD.

BUG=236376
TEST=installer_util_unittests.exe --gtest_filter=InstallerStateTest.RemoveOldVersionDirs

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=197434

[Will Harris, 2013-04-29 19:49:28]

small fix, this makes these tests pass
and they can be re-enabled on x64.

[robertshield, 2013-04-29 20:04:45]

https://codereview.chromium.org/14105014/diff/1/chrome/installer/test/alterna...
File chrome/installer/test/alternate_version_generator.cc (right):

https://codereview.chromium.org/14105014/diff/1/chrome/installer/test/alterna...
chrome/installer/test/alternate_version_generator.cc:182:
static_cast<int64>(std::numeric_limits<DWORD>::max())) {
Really curious: how does this fix the test?

[Will Harris, 2013-04-29 20:13:15]

On 2013/04/29 19:49:28, Will Harris wrote:
> small fix, this makes these tests pass
> and they can be re-enabled on x64.

before this - the call to MappedFile::Initialize fails
because static_cast<int64>(std::numeric_limits<size_t>::max())
evaluates to (int64)-1 on 64bit (size_t == long long) meaning
that the comparison statement always evaluates to false
and error on line 197 fails the test.  The test was therefore
disabled on x64 :)

[robertshield, 2013-04-30 14:16:32]

lgtm

[commit-bot: I haz the power, 2013-04-30 16:25:08]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/wfh@chromium.org/14105014/1

[commit-bot: I haz the power, 2013-04-30 19:50:22]

Change committed as 197434