Make file_util::CreateDirectory return an error, not just a bool

base/file_util_posix.cc

Index: base/file_util_posix.cc
diff --git a/base/file_util_posix.cc b/base/file_util_posix.cc
index 7ef09a200de29c96c1f3f49e7002e50798488ec0..9845f54817d141de36ab5a2fc118fd800b3aeb8e 100644
--- a/base/file_util_posix.cc
+++ b/base/file_util_posix.cc
@@ -519,7 +519,8 @@ bool CreateNewTempDirectory(const FilePath::StringType& prefix,
   return CreateTemporaryDirInDirImpl(tmpdir, TempFileName(), new_temp_path);
 }
 
-bool CreateDirectory(const FilePath& full_path) {
+bool CreateDirectoryAndGetError(const FilePath& full_path,
+                                base::PlatformFileError* error) {
   base::ThreadRestrictions::AssertIOAllowed();  // For call to mkdir().
   std::vector<FilePath> subpaths;
 
@@ -543,8 +544,12 @@ bool CreateDirectory(const FilePath& full_path) {
     // due to the the directory appearing out of thin air. This can occur if
     // two processes are trying to create the same file system tree at the same
     // time. Check to see if it exists and make sure it is a directory.
-    if (!DirectoryExists(*i))
+    int saved_errno = errno;
+    if (!DirectoryExists(*i)) {
+      if (error)
+        *error = base::ErrnoToPlatformFileError(saved_errno);
       return false;
+    }
   }
   return true;
 }