Upgrade to golang protobuf api v2

Major operations:
 * Fix the go_package entries to be consistent, as the new tool
   complains when it doesn't have a '/'.
 * Regenerate with the new protoc-gen-go tool.
 * github.com/golang/protobuf -> google.golang.org/protobuf
 * proto.[Un]MarshalText -> prototext.[Un]Marshal

Change-Id: Ie1147bd2457fafb66ba555461b3bf14f0561a25d
diff --git a/cmd/extract_apks/main_test.go b/cmd/extract_apks/main_test.go
index c3e6a2d..9fcf324 100644
--- a/cmd/extract_apks/main_test.go
+++ b/cmd/extract_apks/main_test.go
@@ -19,7 +19,7 @@
 	"reflect"
 	"testing"
 
-	"github.com/golang/protobuf/proto"
+	"google.golang.org/protobuf/encoding/prototext"
 
 	bp "android/soong/cmd/extract_apks/bundle_proto"
 	"android/soong/third_party/zip"
@@ -253,7 +253,7 @@
 	}
 	for _, testCase := range testCases {
 		var toc bp.BuildApksResult
-		if err := proto.UnmarshalText(testCase.protoText, &toc); err != nil {
+		if err := prototext.Unmarshal([]byte(testCase.protoText), &toc); err != nil {
 			t.Fatal(err)
 		}
 		for _, config := range testCase.configs {
@@ -407,7 +407,7 @@
 	}
 	for _, testCase := range testCases {
 		var toc bp.BuildApksResult
-		if err := proto.UnmarshalText(testCase.protoText, &toc); err != nil {
+		if err := prototext.Unmarshal([]byte(testCase.protoText), &toc); err != nil {
 			t.Fatal(err)
 		}
 		for _, config := range testCase.configs {