ref: Change context mutators from SetFoo to WithFoo.

The motivation for this change is consistency, so our API becomes
easier to use.

Before this CL we were using the WithFoo style in the context
package, but the SetFoo style elsewhere, sometimes with an extra
"Context" thrown in for kicks.  After this CL we use WithFoo (and
GetFoo) everywhere.

Change-Id: Idc6959e4ea76ca6bd36501f4002145ffa8835c04
MultiPart: 2/4
diff --git a/profiles/internal/rpc/full_test.go b/profiles/internal/rpc/full_test.go
index 838c43b..7729e21 100644
--- a/profiles/internal/rpc/full_test.go
+++ b/profiles/internal/rpc/full_test.go
@@ -234,7 +234,7 @@
 
 func startServerWS(t *testing.T, ctx *context.T, principal security.Principal, sm stream.Manager, ns namespace.T, name string, disp rpc.Dispatcher, shouldUseWebsocket websocketMode, opts ...rpc.ServerOpt) (naming.Endpoint, rpc.Server) {
 	vlog.VI(1).Info("InternalNewServer")
-	ctx, _ = v23.SetPrincipal(ctx, principal)
+	ctx, _ = v23.WithPrincipal(ctx, principal)
 	server, err := testInternalNewServer(ctx, sm, ns, principal, opts...)
 	if err != nil {
 		t.Errorf("InternalNewServer failed: %v", err)
@@ -534,7 +534,7 @@
 	// (that are blessed by pprovider).
 	pclient.BlessingStore().Set(bless(pprovider, pclient, "client"), "root")
 
-	clientCtx, _ := v23.SetPrincipal(ctx, pclient)
+	clientCtx, _ := v23.WithPrincipal(ctx, pclient)
 	client, err := InternalNewClient(mgr, ns)
 	if err != nil {
 		t.Fatal(err)
@@ -639,7 +639,7 @@
 		t.Fatal(err)
 	}
 	defer client.Close()
-	ctx, _ = v23.SetPrincipal(ctx, pclient)
+	ctx, _ = v23.WithPrincipal(ctx, pclient)
 	if _, err := client.StartCall(ctx, "mountpoint/server", "Closure", nil); verror.ErrorID(err) != verror.ErrNotTrusted.ID {
 		t.Errorf("Got error %v (errorid=%v), want errorid=%v", err, verror.ErrorID(err), verror.ErrNotTrusted.ID)
 	}
@@ -716,7 +716,7 @@
 		b                = createBundleWS(t, ctx, pserver, &testServer{}, shouldUseWebsocket)
 	)
 	defer b.cleanup(t, ctx)
-	ctx, _ = v23.SetPrincipal(ctx, pclient)
+	ctx, _ = v23.WithPrincipal(ctx, pclient)
 	for _, test := range tests {
 		vlog.VI(1).Infof("%s client.StartCall", name(test))
 		vname := test.name
@@ -783,7 +783,7 @@
 		b                = createBundle(t, ctx, pserver, &testServer{})
 	)
 	defer b.cleanup(t, ctx)
-	ctx, _ = v23.SetPrincipal(ctx, pclient)
+	ctx, _ = v23.WithPrincipal(ctx, pclient)
 	call, err := b.client.StartCall(ctx, "mountpoint/server/suffix", "Echo", v{"foo"})
 	if err != nil {
 		t.Fatalf(`client.StartCall got error "%v"`, err)
@@ -826,7 +826,7 @@
 	defer shutdown()
 	defer b.cleanup(t, ctx)
 
-	ctx, _ = v23.SetPrincipal(ctx, pclient)
+	ctx, _ = v23.WithPrincipal(ctx, pclient)
 	tests := []struct {
 		granter                       rpc.Granter
 		startErrID, finishErrID       verror.IDAction
@@ -971,7 +971,7 @@
 
 	for _, test := range tests {
 		pclient := setClientBlessings(test.Requirements)
-		ctx, _ = v23.SetPrincipal(ctx, pclient)
+		ctx, _ = v23.WithPrincipal(ctx, pclient)
 		client, err := InternalNewClient(sm, ns)
 		if err != nil {
 			t.Fatalf("InternalNewClient(%+v) failed: %v", test.Requirements, err)
@@ -1132,7 +1132,7 @@
 		defer client.Close()
 
 		pclient.BlessingStore().Set(test.blessings, "server")
-		ctx, _ := v23.SetPrincipal(ctx, pclient)
+		ctx, _ := v23.WithPrincipal(ctx, pclient)
 		err = client.Call(ctx, test.name, test.method, test.args, makeResultPtrs(test.results))
 		if err != nil && test.authorized {
 			t.Errorf(`%s client.Call got error: "%v", wanted the RPC to succeed`, name, err)
@@ -1207,7 +1207,7 @@
 	b := createBundle(t, ctx, pserver, &testServer{})
 	defer b.cleanup(t, ctx)
 
-	ctx, _ = v23.SetPrincipal(ctx, pclient)
+	ctx, _ = v23.WithPrincipal(ctx, pclient)
 	tests := []struct {
 		blessings security.Blessings
 		errID     verror.IDAction
@@ -1268,7 +1268,7 @@
 	}
 	defer client.Close()
 
-	ctx, _ = v23.SetPrincipal(ctx, pclient)
+	ctx, _ = v23.WithPrincipal(ctx, pclient)
 	var gotServer, gotClient string
 	if err := client.Call(ctx, "mountpoint/server/suffix", "EchoBlessings", nil, []interface{}{&gotServer, &gotClient}); err != nil {
 		t.Fatalf("Finish failed: %v", err)
@@ -1301,7 +1301,7 @@
 	if b.client, err = InternalNewClient(b.sm, b.ns); err != nil {
 		t.Fatalf("InternalNewClient failed: %v", err)
 	}
-	ctx, _ = v23.SetPrincipal(ctx, pclient)
+	ctx, _ = v23.WithPrincipal(ctx, pclient)
 	call := func() error {
 		var got string
 		if err := b.client.Call(ctx, "mountpoint/server/aclAuth", "Echo", []interface{}{"batman"}, []interface{}{&got}); err != nil {
@@ -1380,7 +1380,7 @@
 	)
 	defer b.cleanup(t, ctx)
 
-	ctx, _ = v23.SetPrincipal(ctx, pclient)
+	ctx, _ = v23.WithPrincipal(ctx, pclient)
 	ctx, cancel := context.WithCancel(ctx)
 	_, err := b.client.StartCall(ctx, "mountpoint/server/suffix", "CancelStreamReader", []interface{}{})
 	if err != nil {
@@ -1401,7 +1401,7 @@
 	)
 	defer b.cleanup(t, ctx)
 
-	ctx, _ = v23.SetPrincipal(ctx, pclient)
+	ctx, _ = v23.WithPrincipal(ctx, pclient)
 	ctx, cancel := context.WithCancel(ctx)
 	call, err := b.client.StartCall(ctx, "mountpoint/server/suffix", "CancelStreamIgnorer", []interface{}{})
 	if err != nil {
@@ -1444,7 +1444,7 @@
 	)
 	defer b.cleanup(t, ctx)
 
-	ctx, _ = v23.SetPrincipal(ctx, pclient)
+	ctx, _ = v23.WithPrincipal(ctx, pclient)
 	call, err := b.client.StartCall(ctx, "mountpoint/server/suffix", "RecvInGoroutine", []interface{}{})
 	if err != nil {
 		t.Fatalf("StartCall failed: %v", err)
@@ -1490,7 +1490,7 @@
 	publisher.AddServer("/@2@tcp@localhost:10000@@1000000@2000000@@")
 	publisher.AddServer("/@2@tcp@localhost:10001@@2000000@3000000@@")
 
-	ctx, _ = v23.SetPrincipal(ctx, pclient)
+	ctx, _ = v23.WithPrincipal(ctx, pclient)
 	_, err := b.client.StartCall(ctx, "incompatible/suffix", "Echo", []interface{}{"foo"}, options.NoRetry{})
 	if verror.ErrorID(err) != verror.ErrNoServers.ID {
 		t.Errorf("Expected error %s, found: %v", verror.ErrNoServers, err)
@@ -1647,7 +1647,7 @@
 	}
 
 	// A call should fail if the principal in the ctx is nil and SecurityNone is not specified.
-	ctx, err = v23.SetPrincipal(ctx, nil)
+	ctx, err = v23.WithPrincipal(ctx, nil)
 	if err != nil {
 		t.Fatalf("failed to set principal: %v", err)
 	}
@@ -1709,7 +1709,7 @@
 			return nil, err
 		}
 		defer client.Close()
-		ctx, _ = v23.SetPrincipal(ctx, pclient)
+		ctx, _ = v23.WithPrincipal(ctx, pclient)
 		call, err := client.StartCall(ctx, server, "Closure", nil)
 		if err != nil {
 			return nil, err
@@ -1777,7 +1777,7 @@
 		if noDischarges {
 			opts = append(opts, NoDischarges{})
 		}
-		ctx, _ = v23.SetPrincipal(ctx, pclient)
+		ctx, _ = v23.WithPrincipal(ctx, pclient)
 		if _, err = client.StartCall(ctx, "mountpoint/testServer", "Closure", nil, opts...); err != nil {
 			t.Fatalf("failed to StartCall: %v", err)
 		}
@@ -1839,7 +1839,7 @@
 	if err != nil {
 		t.Error(err)
 	}
-	ctx, _ = v23.SetPrincipal(ctx, pdischargeClient)
+	ctx, _ = v23.WithPrincipal(ctx, pdischargeClient)
 	dc.PrepareDischarges(ctx, []security.Caveat{tpcav2}, security.DischargeImpetus{})
 
 	// Ensure that discharger1 was not called and discharger2 was called.
@@ -1871,7 +1871,7 @@
 	defer serverSM.Shutdown()
 	rid := serverSM.RoutingID()
 
-	ctx, _ = v23.SetPrincipal(ctx, pclient)
+	ctx, _ = v23.WithPrincipal(ctx, pclient)
 
 	newClient := func() rpc.Client {
 		rid, err := naming.NewRoutingID()
@@ -1963,7 +1963,7 @@
 	defer smc.Shutdown()
 	defer client.Close()
 
-	ctx, _ = v23.SetPrincipal(ctx, pclient)
+	ctx, _ = v23.WithPrincipal(ctx, pclient)
 	// The call should succeed when the server presents the same public as the opt...
 	if _, err = client.StartCall(ctx, mountName, "Closure", nil, options.SkipServerEndpointAuthorization{}, options.ServerPublicKey{pserver.PublicKey()}); err != nil {
 		t.Errorf("Expected call to succeed but got %v", err)
@@ -2027,7 +2027,7 @@
 		t.Fatalf("failed to create client: %v", err)
 	}
 	defer client.Close()
-	ctx, _ = v23.SetPrincipal(ctx, pclient)
+	ctx, _ = v23.WithPrincipal(ctx, pclient)
 	dc := InternalNewDischargeClient(ctx, client, 0)
 
 	// Fetch discharges for tpcav.