Replace base::File wrapping with typemapping.

third_party/WebKit/public/platform/modules/hyphenation/hyphenation.mojom

Index: third_party/WebKit/public/platform/modules/hyphenation/hyphenation.mojom
diff --git a/third_party/WebKit/public/platform/modules/hyphenation/hyphenation.mojom b/third_party/WebKit/public/platform/modules/hyphenation/hyphenation.mojom
index 65c3d3c830d3b838b03980396ae4c620a394673c..19cf71dc7c22d0413499ce5a0f9b6c93965c8e5d 100644
--- a/third_party/WebKit/public/platform/modules/hyphenation/hyphenation.mojom
+++ b/third_party/WebKit/public/platform/modules/hyphenation/hyphenation.mojom
@@ -4,9 +4,12 @@
 
 module blink.mojom;
 
+import "mojo/common/common_custom_types.mojom";
+
 // Loads hyphenation dictionary.
 interface Hyphenation {
   // Returns a handle to the raw hyphneation dictionary.
   [Sync]
-  OpenDictionary(string locale) => (handle? hyphenation_dictionary_handle);
+  OpenDictionary(string locale) => (
+      mojo.common.mojom.File? hyphenation_dictionary_handle);
 };