base/ header cleanup. Forward declaration instead of including.

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/3068004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@53969 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/zygote_main_linux.cc b/chrome/browser/zygote_main_linux.cc
index 51a658e..dee2839 100644
--- a/chrome/browser/zygote_main_linux.cc
+++ b/chrome/browser/zygote_main_linux.cc
@@ -21,6 +21,7 @@
 #include "base/basictypes.h"
 #include "base/command_line.h"
 #include "base/eintr_wrapper.h"
+#include "base/file_path.h"
 #include "base/global_descriptors_posix.h"
 #include "base/hash_tables.h"
 #include "base/linux_util.h"