Use realpath() to find the path to the extension unpack dir on posix systems.

chrome/browser/utility_process_host.cc

Index: chrome/browser/utility_process_host.cc
diff --git a/chrome/browser/utility_process_host.cc b/chrome/browser/utility_process_host.cc
index 2f7ce5d53573bdb234db70921eeb732d397fedf3..e75339568991bab78b5c5aed3a5be68f69c60f63 100644
--- a/chrome/browser/utility_process_host.cc
+++ b/chrome/browser/utility_process_host.cc
@@ -26,9 +26,26 @@ UtilityProcessHost::~UtilityProcessHost() {
 }
 
 bool UtilityProcessHost::StartExtensionUnpacker(const FilePath& extension) {
+  FilePath initial_path = extension.DirName();
+  FilePath real_path;
+
+#if defined(OS_POSIX)
+  if (!file_util::RealPath(initial_path, &real_path)) {
+    real_path = initial_path;
+  }
+#else
+  // TODO(skerner): For windows, we need to expand NTFS junctions.
+  // http://crbug.com/13044
+  real_path = initial_path;
+#endif
+
+  // TODO(skerner): Remove this logging once we understand crbug.com/35198
+  LOG(INFO) << "initial_path: " << initial_path.value();
+  LOG(INFO) << "real_path: " << real_path.value();
+
   // Grant the subprocess access to the entire subdir the extension file is
   // in, so that it can unpack to that dir.
-  if (!StartProcess(extension.DirName()))
+  if (!StartProcess(real_path))
     return false;
 
   Send(new UtilityMsg_UnpackExtension(extension));