Minor tweaks to get chrome-ui://extensions working on the Mac.

Review URL: http://codereview.chromium.org/42627

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@12586 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/extensions/extensions_service.cc b/chrome/browser/extensions/extensions_service.cc
index 2c3451b..6b73b65b 100644
--- a/chrome/browser/extensions/extensions_service.cc
+++ b/chrome/browser/extensions/extensions_service.cc
@@ -184,8 +184,15 @@
   frontend_ = frontend;
   alert_on_error_ = false;
 
+#if defined(OS_WIN)
+  // On POSIX, AbsolutePath() calls realpath() which returns NULL if
+  // it does not exist.  Instead we absolute-ify after creation in
+  // case that is needed.
+  // TODO(port): does this really need to happen before
+  // CreateDirectory() on Windows?
   if (!file_util::AbsolutePath(&install_directory_))
     NOTREACHED();
+#endif
 
   scoped_ptr<ExtensionList> extensions(new ExtensionList);
 
@@ -197,6 +204,11 @@
     return;
   }
 
+#if !defined(OS_WIN)
+  if (!file_util::AbsolutePath(&install_directory_))
+    NOTREACHED();
+#endif
+
   LOG(INFO) << "Loading installed extensions...";
 
   // Find all child directories in the install directory and load their