Remove some unused NaCl srpc methods (AttachService, ctor variant).

Remove a couple unused fwd declarations and make a Getter
const while I'm messing with that file.

BUG=none

Review URL: https://codereview.chromium.org/977893003

Cr-Commit-Position: refs/heads/master@{#319159}

components/nacl/renderer/plugin/srpc_client.cc

@@ -191,9 +191,4 @@ bool SrpcClient::Invoke(const std::string& method_name, SrpcParams* params) {
   return true;
 }
 
-void SrpcClient::AttachService(NaClSrpcService* service, void* instance_data) {
-  srpc_channel_.server = service;
-  srpc_channel_.server_instance_data = instance_data;
-}
-
 }  // namespace plugin

components/nacl/renderer/plugin/srpc_client.h

@@ -23,9 +23,7 @@ class DescWrapper;
 
 namespace plugin {
 
-class ErrorInfo;
 class MethodInfo;
-class Plugin;
 class SrpcParams;
 
 //  SrpcClient represents an SRPC connection to a client.
@@ -46,12 +44,9 @@ class SrpcClient {
   //  Invoke an SRPC method.
   bool Invoke(const std::string& method_name, SrpcParams* params);
   // Get the error status from that last method invocation
-  NaClSrpcError GetLastError() { return last_error_; }
+  NaClSrpcError GetLastError() const { return last_error_; }
   bool InitParams(const std::string& method_name, SrpcParams* params);
 
-  // Attach a service for reverse-direction (from .nexe) RPCs.
-  void AttachService(NaClSrpcService* service, void* instance_data);
-
  private:
   NACL_DISALLOW_COPY_AND_ASSIGN(SrpcClient);
   SrpcClient();

components/nacl/renderer/plugin/srpc_params.h

@@ -21,12 +21,6 @@ class SrpcParams {
     memset(outs_, 0, sizeof(outs_));
   }
 
-  SrpcParams(const char* in_types, const char* out_types) {
-    if (!Init(in_types, out_types)) {
-      FreeAll();
-    }
-  }
-
   ~SrpcParams() {
     FreeAll();
   }