crypto/tls: revert "add HandshakeContext method to Conn"

This reverts CL 246338.

Reason for revert: waiting for 1.17 release cycle

Updates #32406

Change-Id: I074379039041e086c62271d689b4b7f442281663
Reviewed-on: https://go-review.googlesource.com/c/go/+/269697
Run-TryBot: Johan Brandhorst-Satzkorn <johan.brandhorst@gmail.com>
Run-TryBot: Katie Hockman <katie@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Katie Hockman <katie@golang.org>
Trust: Katie Hockman <katie@golang.org>
Trust: Roland Shoemaker <roland@golang.org>

conn.go

@@ -8,7 +8,6 @@ package tls
 
 import (
 	"bytes"
-	"context"
 	"crypto/cipher"
 	"crypto/subtle"
 	"crypto/x509"
@@ -28,7 +27,7 @@ type Conn struct {
 	// constant
 	conn        net.Conn
 	isClient    bool
-	handshakeFn func(context.Context) error // (*Conn).clientHandshake or serverHandshake
+	handshakeFn func() error // (*Conn).clientHandshake or serverHandshake
 
 	// handshakeStatus is 1 if the connection is currently transferring
 	// application data (i.e. is not currently processing a handshake).
@@ -1191,7 +1190,7 @@ func (c *Conn) handleRenegotiation() error {
 	defer c.handshakeMutex.Unlock()
 
 	atomic.StoreUint32(&c.handshakeStatus, 0)
-	if c.handshakeErr = c.clientHandshake(context.Background()); c.handshakeErr == nil {
+	if c.handshakeErr = c.clientHandshake(); c.handshakeErr == nil {
 		c.handshakes++
 	}
 	return c.handshakeErr
@@ -1374,61 +1373,8 @@ func (c *Conn) closeNotify() error {
 // first Read or Write will call it automatically.
 //
 // For control over canceling or setting a timeout on a handshake, use
-// HandshakeContext or the Dialer's DialContext method instead.
+// the Dialer's DialContext method.
 func (c *Conn) Handshake() error {
-	return c.HandshakeContext(context.Background())
-}
-
-// HandshakeContext runs the client or server handshake
-// protocol if it has not yet been run.
-//
-// The provided Context must be non-nil. If the context is canceled before
-// the handshake is complete, the handshake is interrupted and an error is returned.
-// Once the handshake has completed, cancellation of the context will not affect the
-// connection.
-//
-// Most uses of this package need not call HandshakeContext explicitly: the
-// first Read or Write will call it automatically.
-func (c *Conn) HandshakeContext(ctx context.Context) error {
-	// Delegate to unexported method for named return
-	// without confusing documented signature.
-	return c.handshakeContext(ctx)
-}
-
-func (c *Conn) handshakeContext(ctx context.Context) (ret error) {
-	handshakeCtx, cancel := context.WithCancel(ctx)
-	// Note: defer this before starting the "interrupter" goroutine
-	// so that we can tell the difference between the input being canceled and
-	// this cancellation. In the former case, we need to close the connection.
-	defer cancel()
-
-	// Start the "interrupter" goroutine, if this context might be canceled.
-	// (The background context cannot).
-	//
-	// The interrupter goroutine waits for the input context to be done and
-	// closes the connection if this happens before the function returns.
-	if ctx.Done() != nil {
-		done := make(chan struct{})
-		interruptRes := make(chan error, 1)
-		defer func() {
-			close(done)
-			if ctxErr := <-interruptRes; ctxErr != nil {
-				// Return context error to user.
-				ret = ctxErr
-			}
-		}()
-		go func() {
-			select {
-			case <-handshakeCtx.Done():
-				// Close the connection, discarding the error
-				_ = c.conn.Close()
-				interruptRes <- handshakeCtx.Err()
-			case <-done:
-				interruptRes <- nil
-			}
-		}()
-	}
-
 	c.handshakeMutex.Lock()
 	defer c.handshakeMutex.Unlock()
 
@@ -1442,7 +1388,7 @@ func (c *Conn) handshakeContext(ctx context.Context) (ret error) {
 	c.in.Lock()
 	defer c.in.Unlock()
 
-	c.handshakeErr = c.handshakeFn(handshakeCtx)
+	c.handshakeErr = c.handshakeFn()
 	if c.handshakeErr == nil {
 		c.handshakes++
 	} else {