Do not display warnings for file:/// extension permissions.

chrome/common/extensions/extension_permission_set_unittest.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/common/extensions/extension_permission_set.h"
 
 #include "base/logging.h"
 #include "base/path_service.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/common/chrome_paths.h"
@@ skipping 854 matching lines @@
     scriptable_hosts.AddPattern(
         URLPattern(URLPattern::SCHEME_HTTP, "http://*.example.com/*"));
 
     expected.insert("*.google.com");
     expected.insert("*.example.com");
 
     perm_set = new ExtensionPermissionSet(
         empty_perms, explicit_hosts, scriptable_hosts);
     EXPECT_EQ(expected, perm_set->GetDistinctHostsForDisplay());
   }
+
+  {
+    // We don't display warnings for file URLs because they are off by default.
+    SCOPED_TRACE("file urls");
+    explicit_hosts.ClearPatterns();
+    scriptable_hosts.ClearPatterns();
+    expected.clear();
+
+    explicit_hosts.AddPattern(
+        URLPattern(URLPattern::SCHEME_FILE, "file:///*"));
+
+    perm_set = new ExtensionPermissionSet(
+        empty_perms, explicit_hosts, scriptable_hosts);
+    EXPECT_EQ(expected, perm_set->GetDistinctHostsForDisplay());
+  }
 }
 
 TEST(ExtensionPermissionSetTest, GetDistinctHostsForDisplay_ComIsBestRcd) {
   scoped_refptr<ExtensionPermissionSet> perm_set;
   ExtensionAPIPermissionSet empty_perms;
   URLPatternSet explicit_hosts;
   URLPatternSet scriptable_hosts;
   explicit_hosts.AddPattern(
       URLPattern(URLPattern::SCHEME_HTTP, "http://www.foo.ca/path"));
   explicit_hosts.AddPattern(
@@ skipping 196 matching lines @@
   AddPattern(&non_empty_extent, "http://www.google.com/*");
 
   perm_set = new ExtensionPermissionSet(
       empty_apis, non_empty_extent, empty_extent);
   EXPECT_FALSE(perm_set->IsEmpty());
 
   perm_set = new ExtensionPermissionSet(
       empty_apis, empty_extent, non_empty_extent);
   EXPECT_FALSE(perm_set->IsEmpty());
 }