go.image: use golang.org/x/... import paths

LGTM=bradfitz, rsc
R=rsc, bradfitz
CC=golang-codereviews
https://golang.org/cl/169090043

cmd/webp-manual-test/main.go

@@ -16,8 +16,8 @@ import (
 	"sort"
 	"strings"
 
-	"code.google.com/p/go.image/webp"
-	"code.google.com/p/go.image/webp/nycbcra"
+	"golang.org/x/image/webp"
+	"golang.org/x/image/webp/nycbcra"
 )
 
 var (

riff/example_test.go

@@ -11,7 +11,7 @@ import (
 	"log"
 	"strings"
 
-	"code.google.com/p/go.image/riff"
+	"golang.org/x/image/riff"
 )
 
 func ExampleReader() {

tiff/reader.go

@@ -16,7 +16,7 @@ import (
 	"io"
 	"io/ioutil"
 
-	"code.google.com/p/go.image/tiff/lzw"
+	"golang.org/x/image/tiff/lzw"
 )
 
 // A FormatError reports that the input is not a valid TIFF image.

webp/decode.go

@@ -15,10 +15,10 @@ import (
 	"image/color"
 	"io"
 
-	"code.google.com/p/go.image/riff"
-	"code.google.com/p/go.image/vp8"
-	"code.google.com/p/go.image/vp8l"
-	"code.google.com/p/go.image/webp/nycbcra"
+	"golang.org/x/image/riff"
+	"golang.org/x/image/vp8"
+	"golang.org/x/image/vp8l"
+	"golang.org/x/image/webp/nycbcra"
 )
 
 var errInvalidFormat = errors.New("webp: invalid format")

webp/decode_test.go

@@ -14,7 +14,7 @@ import (
 	"strings"
 	"testing"
 
-	"code.google.com/p/go.image/webp/nycbcra"
+	"golang.org/x/image/webp/nycbcra"
 )
 
 // hex is like fmt.Sprintf("% x", x) but also inserts dots every 16 bytes, to