Fix native extension lookup

runtime/bin/loader.cc

Index: runtime/bin/loader.cc
diff --git a/runtime/bin/loader.cc b/runtime/bin/loader.cc
index 122e851a302bb167d097aadd5480be963028b998..4d35728d228eeeffe234ec83ad1fd1bf6a310ac7 100644
--- a/runtime/bin/loader.cc
+++ b/runtime/bin/loader.cc
@@ -8,6 +8,7 @@
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
 #include "bin/extensions.h"
+#include "bin/file.h"
 #include "bin/lockers.h"
 #include "bin/utils.h"
 
@@ -261,12 +262,10 @@ static bool LibraryHandleError(Dart_Handle library, Dart_Handle error) {
 }
 
 
-static bool IsWindowsHost() {
-#if defined(TARGET_OS_WINDOWS)
-  return true;
-#else  // defined(TARGET_OS_WINDOWS)
-  return false;
-#endif  // defined(TARGET_OS_WINDOWS)
+static bool PathContainsSeparator(const char* path) {
+  return (strchr(path, '/') != NULL) ||
+         ((strncmp(File::PathSeparator(), "/", 1) != 0) &&
+          (strstr(path, File::PathSeparator()) != NULL));
 }
 
 
@@ -300,7 +299,6 @@ bool Loader::ProcessResultLocked(Loader* loader, Loader::IOResult* result) {
     return false;
   }
 
-
   if (result->tag == _Dart_kImportExtension) {
     ASSERT(library_uri != Dart_Null());
     Dart_Handle library = Dart_LookupLibrary(library_uri);
@@ -320,10 +318,10 @@ bool Loader::ProcessResultLocked(Loader* loader, Loader::IOResult* result) {
       lib_path = lib_uri;
     }
     const char* extension_path = DartUtils::RemoveScheme(extension_uri);
-    if (strchr(extension_path, '/') != NULL ||
-        (IsWindowsHost() && strchr(extension_path, '\\') != NULL)) {
+    if (!File::IsAbsolutePath(extension_path) &&
+        PathContainsSeparator(extension_path)) {
       loader->error_ = DartUtils::NewError(
-          "Relative paths for dart extensions are not supported: '%s'",
+          "Native extension path must be absolute, or simply the file name: %s",
           extension_path);
       return false;
     }