Some ui/BUILD.gn fixes.

third_party/mozilla/BUILD.gn

Index: third_party/mozilla/BUILD.gn
diff --git a/third_party/mozilla/BUILD.gn b/third_party/mozilla/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..ca41a3d0d955663560f16d1296f4e84c5fb15575
--- /dev/null
+++ b/third_party/mozilla/BUILD.gn
@@ -0,0 +1,34 @@
+# Copyright 2014 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.
+
+component("mozilla") {
+  sources = [
+    "ComplexTextInputPanel.h",
+    "ComplexTextInputPanel.mm",
+    "MozillaExport.h",
+    "NSPasteboard+Utils.h",
+    "NSPasteboard+Utils.mm",
+    "NSScreen+Utils.h",
+    "NSScreen+Utils.m",
+    "NSString+Utils.h",
+    "NSString+Utils.mm",
+    "NSURL+Utils.h",
+    "NSURL+Utils.m",
+    "NSWorkspace+Utils.h",
+    "NSWorkspace+Utils.m",
+  ]
+
+  defines = [
+    "MOZILLA_IMPLEMENTATION",
+  ]
+
+  deps = [
+    "//url",
+  ]
+
+  if (is_component_build && (is_mac || is_ios)) {
+    # Needed to link to Obj-C static libraries.
+    ldflags = [ "-Wl,-ObjC" ]
+  }
+}