diff --git a/vendor/google.golang.org/appengine/internal/api_classic.go b/vendor/google.golang.org/appengine/internal/api_classic.go
new file mode 100644
index 0000000..f0f40b2
--- /dev/null
+++ b/vendor/google.golang.org/appengine/internal/api_classic.go
@@ -0,0 +1,169 @@
+// Copyright 2015 Google Inc. All rights reserved.
+// Use of this source code is governed by the Apache 2.0
+// license that can be found in the LICENSE file.
+
+// +build appengine
+
+package internal
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"time"
+
+	"appengine"
+	"appengine_internal"
+	basepb "appengine_internal/base"
+
+	"github.com/golang/protobuf/proto"
+	netcontext "golang.org/x/net/context"
+)
+
+var contextKey = "holds an appengine.Context"
+
+// fromContext returns the App Engine context or nil if ctx is not
+// derived from an App Engine context.
+func fromContext(ctx netcontext.Context) appengine.Context {
+	c, _ := ctx.Value(&contextKey).(appengine.Context)
+	return c
+}
+
+// This is only for classic App Engine adapters.
+func ClassicContextFromContext(ctx netcontext.Context) (appengine.Context, error) {
+	c := fromContext(ctx)
+	if c == nil {
+		return nil, errNotAppEngineContext
+	}
+	return c, nil
+}
+
+func withContext(parent netcontext.Context, c appengine.Context) netcontext.Context {
+	ctx := netcontext.WithValue(parent, &contextKey, c)
+
+	s := &basepb.StringProto{}
+	c.Call("__go__", "GetNamespace", &basepb.VoidProto{}, s, nil)
+	if ns := s.GetValue(); ns != "" {
+		ctx = NamespacedContext(ctx, ns)
+	}
+
+	return ctx
+}
+
+func IncomingHeaders(ctx netcontext.Context) http.Header {
+	if c := fromContext(ctx); c != nil {
+		if req, ok := c.Request().(*http.Request); ok {
+			return req.Header
+		}
+	}
+	return nil
+}
+
+func ReqContext(req *http.Request) netcontext.Context {
+	return WithContext(netcontext.Background(), req)
+}
+
+func WithContext(parent netcontext.Context, req *http.Request) netcontext.Context {
+	c := appengine.NewContext(req)
+	return withContext(parent, c)
+}
+
+type testingContext struct {
+	appengine.Context
+
+	req *http.Request
+}
+
+func (t *testingContext) FullyQualifiedAppID() string { return "dev~testcontext" }
+func (t *testingContext) Call(service, method string, _, _ appengine_internal.ProtoMessage, _ *appengine_internal.CallOptions) error {
+	if service == "__go__" && method == "GetNamespace" {
+		return nil
+	}
+	return fmt.Errorf("testingContext: unsupported Call")
+}
+func (t *testingContext) Request() interface{} { return t.req }
+
+func ContextForTesting(req *http.Request) netcontext.Context {
+	return withContext(netcontext.Background(), &testingContext{req: req})
+}
+
+func Call(ctx netcontext.Context, service, method string, in, out proto.Message) error {
+	if ns := NamespaceFromContext(ctx); ns != "" {
+		if fn, ok := NamespaceMods[service]; ok {
+			fn(in, ns)
+		}
+	}
+
+	if f, ctx, ok := callOverrideFromContext(ctx); ok {
+		return f(ctx, service, method, in, out)
+	}
+
+	// Handle already-done contexts quickly.
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
+
+	c := fromContext(ctx)
+	if c == nil {
+		// Give a good error message rather than a panic lower down.
+		return errNotAppEngineContext
+	}
+
+	// Apply transaction modifications if we're in a transaction.
+	if t := transactionFromContext(ctx); t != nil {
+		if t.finished {
+			return errors.New("transaction context has expired")
+		}
+		applyTransaction(in, &t.transaction)
+	}
+
+	var opts *appengine_internal.CallOptions
+	if d, ok := ctx.Deadline(); ok {
+		opts = &appengine_internal.CallOptions{
+			Timeout: d.Sub(time.Now()),
+		}
+	}
+
+	err := c.Call(service, method, in, out, opts)
+	switch v := err.(type) {
+	case *appengine_internal.APIError:
+		return &APIError{
+			Service: v.Service,
+			Detail:  v.Detail,
+			Code:    v.Code,
+		}
+	case *appengine_internal.CallError:
+		return &CallError{
+			Detail:  v.Detail,
+			Code:    v.Code,
+			Timeout: v.Timeout,
+		}
+	}
+	return err
+}
+
+func handleHTTP(w http.ResponseWriter, r *http.Request) {
+	panic("handleHTTP called; this should be impossible")
+}
+
+func logf(c appengine.Context, level int64, format string, args ...interface{}) {
+	var fn func(format string, args ...interface{})
+	switch level {
+	case 0:
+		fn = c.Debugf
+	case 1:
+		fn = c.Infof
+	case 2:
+		fn = c.Warningf
+	case 3:
+		fn = c.Errorf
+	case 4:
+		fn = c.Criticalf
+	default:
+		// This shouldn't happen.
+		fn = c.Criticalf
+	}
+	fn(format, args...)
+}