Convert unit_tests.exe to gyp.

BUG=none
TEST=none
Review URL: http://codereview.chromium.org/126152

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@18441 0039d316-1c4b-4281-b951-d872f2087c98

chrome/chrome.gyp

@@ -3993,7 +3993,6 @@
           'type': 'shared_library',
           'product_name': 'chrome',
           'msvs_guid': 'C0A7EE2C-2A6D-45BE-BA78-6D006FDF52D9',
-          'msvs_existing_vcproj': 'app/chrome_dll.vcproj',
           'include_dirs': [
             'third_party/wtl/include',
           ],