Implement BackgroundFetchManager.fetch() and struct traits

content/common/background_fetch/background_fetch_types.typemap

Index: content/common/background_fetch/background_fetch_types.typemap
diff --git a/content/common/background_fetch/background_fetch_types.typemap b/content/common/background_fetch/background_fetch_types.typemap
new file mode 100644
index 0000000000000000000000000000000000000000..4a00cb1c54c404633bd33ceae698f214461fefad
--- /dev/null
+++ b/content/common/background_fetch/background_fetch_types.typemap
@@ -0,0 +1,18 @@
+# Copyright 2017 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.
+
+mojom = "//third_party/WebKit/public/platform/modules/background_fetch/background_fetch.mojom"
+public_headers =
+    [ "//content/common/background_fetch/background_fetch_types.h" ]
+traits_headers =
+    [ "//content/common/background_fetch/background_fetch_struct_traits.h" ]
+deps = [
+  "//mojo/public/cpp/bindings",
+  "//third_party/WebKit/public:blink_headers",
+]
+type_mappings = [
+  "blink.mojom.BackgroundFetchOptions=content::BackgroundFetchOptions",
+  "blink.mojom.BackgroundFetchRegistration=content::BackgroundFetchRegistration",
+  "blink.mojom.IconDefinition=content::IconDefinition",
+]