internal: add support for std@dev.boringcrypto

Change-Id: Ibe5383c8c9b9ce771b677c2e33a0c2c85621df6d
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/343218
Trust: Julie Qiu <julie@golang.org>
Run-TryBot: Julie Qiu <julie@golang.org>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jamal Carvalho <jamal@golang.org>
diff --git a/internal/frontend/versions.go b/internal/frontend/versions.go
index 7543fa4..a84d182 100644
--- a/internal/frontend/versions.go
+++ b/internal/frontend/versions.go
@@ -355,8 +355,9 @@
 			// std doesn't have actual pseudoversions, so the only ones we
 			// support are "master" and "dev.fuzz".
 			v := version.Master
-			if requestedVersion == stdlib.DevFuzz {
-				v = stdlib.DevFuzz
+			if requestedVersion == stdlib.DevFuzz ||
+				requestedVersion == stdlib.DevBoringCrypto {
+				v = requestedVersion
 			}
 			return fmt.Sprintf("%s (%s)", v, commit[0:7])
 		}
diff --git a/internal/stdlib/stdlib.go b/internal/stdlib/stdlib.go
index faa62a2..96ae3c5 100644
--- a/internal/stdlib/stdlib.go
+++ b/internal/stdlib/stdlib.go
@@ -40,6 +40,9 @@
 
 	// DevFuzz is the branch name for fuzzing in beta.
 	DevFuzz = "dev.fuzz"
+
+	// DevBoringCrypto is the branch name for dev.boringcrypto.
+	DevBoringCrypto = "dev.boringcrypto"
 )
 
 var (
@@ -54,8 +57,9 @@
 
 // SupportedBranches are the branches of the stdlib repo supported by pkgsite.
 var SupportedBranches = map[string]bool{
-	version.Master: true,
-	DevFuzz:        true,
+	version.Master:  true,
+	DevBoringCrypto: true,
+	DevFuzz:         true,
 }
 
 // VersionForTag returns the semantic version for the Go tag, or "" if
@@ -199,8 +203,8 @@
 	var ref plumbing.ReferenceName
 	if v == version.Master {
 		ref = plumbing.HEAD
-	} else if v == DevFuzz {
-		ref = "refs/heads/dev.fuzz"
+	} else if SupportedBranches[v] {
+		ref = plumbing.NewBranchReferenceName(v)
 	} else {
 		tag, err := TagForVersion(v)
 		if err != nil {