Implement TransferableResource StructTraits

This CL also moves out the dependency on skia
resource_format.h to resource_format_utils. This was to avoid
adding skia as a public dependency from the
TransferableResource StructTraits.

BUG=
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review-Url: https://codereview.chromium.org/2020993004
Cr-Commit-Position: refs/heads/master@{#397105}

diff --git a/cc/BUILD.gn b/cc/BUILD.gn
index 3002a9fb..63f80c21 100644
--- a/cc/BUILD.gn
+++ b/cc/BUILD.gn

@@ -394,6 +394,8 @@
     "resources/resource.h",
     "resources/resource_format.cc",
     "resources/resource_format.h",
+    "resources/resource_format_utils.cc",
+    "resources/resource_format_utils.h",
     "resources/resource_pool.cc",
     "resources/resource_pool.h",
     "resources/resource_provider.cc",