Fixing gcc 4.7 building problems.

a) - gcc-4.7 improved the implicit headers that it includes. with
<4.7, the gthr-default.h file always pulls in unistd.h. with >=4.7,
they avoided that include when possible. so code that isn't including
unistd.h itself but needs it now breaks.

b) - narrowing conversion in initiliazation list now raises an
'ill-formed conversion' warning, which causes error when -Werror is
given.

[THIS PART IS NOW REVERTED IN THE PATCH} c) - included patches from pastebin - http://pastebin.com/raw.php?i=p3UKs7Cg

Note - this may not be fixing all the gcc 4.7 build problems for all
parts, but rather than submitting one big-fix-for-all CL, we'd better
do it incrementally (given that all the modification is reasonable and
minor) so that at least some parts get a successful gcc 4.7 build.

BUG=None
TEST=Built successfully using GCC-4.7 under chromium chroot


Review URL: https://chromiumcodereview.appspot.com/10451068

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@140470 0039d316-1c4b-4281-b951-d872f2087c98

diff --git a/ipc/ipc_channel.h b/ipc/ipc_channel.h
index 2aeca1fc..14c375b 100644
--- a/ipc/ipc_channel.h
+++ b/ipc/ipc_channel.h

@@ -8,6 +8,10 @@
 
 #include <string>
 
+#if defined(OS_POSIX)
+#include <sys/types.h>
+#endif
+
 #include "base/compiler_specific.h"
 #include "base/process.h"
 #include "ipc/ipc_channel_handle.h"