Reduce header dependencies in base/

Also adds more explicit #includes for needed things.

Review URL: http://codereview.chromium.org/118162

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@17479 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/base/file_version_info.h b/base/file_version_info.h
index f38d23ff..7e8663904 100644
--- a/base/file_version_info.h
+++ b/base/file_version_info.h
@@ -8,7 +8,6 @@
 #include <string>
 
 #include "base/basictypes.h"
-#include "base/file_path.h"
 #include "base/scoped_ptr.h"
 
 #if defined(OS_WIN)
@@ -22,6 +21,8 @@
 #endif
 #endif
 
+class FilePath;
+
 // Provides a way to access the version information for a file.
 // This is the information you access when you select a file in the Windows
 // explorer, right-click select Properties, then click the Version tab.