godoc: replace x/net/context with context

Change-Id: I5b0508ccf7a912a8f334abcfb32033e120fc7971
Reviewed-on: https://go-review.googlesource.com/c/143717
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/godoc/dl/server.go b/godoc/dl/server.go
index bb86354..6306c1c 100644
--- a/godoc/dl/server.go
+++ b/godoc/dl/server.go
@@ -7,6 +7,7 @@
 package dl
 
 import (
+	"context"
 	"crypto/hmac"
 	"crypto/md5"
 	"encoding/json"
@@ -20,7 +21,6 @@
 	"time"
 
 	"cloud.google.com/go/datastore"
-	"golang.org/x/net/context"
 	"golang.org/x/tools/godoc/env"
 	"golang.org/x/tools/internal/memcache"
 )
diff --git a/godoc/proxy/proxy.go b/godoc/proxy/proxy.go
index f302372..1c1798f 100644
--- a/godoc/proxy/proxy.go
+++ b/godoc/proxy/proxy.go
@@ -8,6 +8,7 @@
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
@@ -18,7 +19,6 @@
 	"strings"
 	"time"
 
-	"golang.org/x/net/context"
 	"golang.org/x/tools/godoc/env"
 )
 
diff --git a/godoc/short/short.go b/godoc/short/short.go
index 5f91cb2..3a399ab 100644
--- a/godoc/short/short.go
+++ b/godoc/short/short.go
@@ -12,6 +12,7 @@
 // TODO(adg): collect statistics on URL visits
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"html/template"
@@ -22,7 +23,6 @@
 	"regexp"
 
 	"cloud.google.com/go/datastore"
-	"golang.org/x/net/context"
 	"golang.org/x/tools/internal/memcache"
 	"google.golang.org/appengine/user"
 )