Replace //net TypeConverters with StructTraits.

net/interfaces/proxy_resolver_service.mojom

Index: net/interfaces/proxy_resolver_service.mojom
diff --git a/net/interfaces/proxy_resolver_service.mojom b/net/interfaces/proxy_resolver_service.mojom
index 2ae84e14e8fa140a758e1b45c68aa51fb209f7e8..ff343de9a2dc2262c59e9882b6e980e99146292b 100644
--- a/net/interfaces/proxy_resolver_service.mojom
+++ b/net/interfaces/proxy_resolver_service.mojom
@@ -26,10 +26,14 @@ struct ProxyServer {
   ProxyScheme scheme;
 
   // |host| and |port| are only valid if |scheme| is not INVALID or DIRECT.
-  string? host;
+  string host;
   uint16 port;
 };
 
+struct ProxyInfo {
+  array<ProxyServer> proxy_servers;
+};
+
 interface ProxyResolver {
   // Use a ProxyResolverRequestClient instead of returning a result so we can
   // cancel in-flight requests by destroying the client.
@@ -37,7 +41,7 @@ interface ProxyResolver {
 };
 
 interface ProxyResolverRequestClient {
-  ReportResult(int32 error, array<ProxyServer>? proxy_servers);
+  ReportResult(int32 error, ProxyInfo proxy_info);

[dcheng, 2016/06/27 03:50:45]

How hard is it to make this work in the bindings without the wrapper struct?

Right now, there's basically two ways to write things: if you're passing a
struct already, you can use array<ProxyServer> or ProxyInfo, but if you're
passing it directly, you have to write ProxyInfo. Can we make this so there's
one canonical way to write this, without the wrapper struct?

[Sam McNally, 2016/06/29 01:42:07]

It's possible to use array<ProxyServer> directly, but I don't think it's
possible to typemap an array. Each user would have to manually convert between
ProxyInfo and mojo::Array<ProxyServer>. The existing ProxyResolver interfaces
only really care about ProxyInfo so this would just make the glue more verbose.

 
   Alert(string error);
   OnError(int32 line_number, string error);