internal/frontend: use frontend.searchMode to determine route tag

The search mode is detected automatically when it is not set
by the client. This ensures that all searches are correctly
tagged when coming from the homepage where the mode is not
explictly set.

Change-Id: I89954e890175de8cff7be2e8ef773d565c6b845c
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/443338
Run-TryBot: Jamal Carvalho <jamal@golang.org>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
diff --git a/internal/frontend/server.go b/internal/frontend/server.go
index bef46c4..5ba2ae9 100644
--- a/internal/frontend/server.go
+++ b/internal/frontend/server.go
@@ -381,11 +381,7 @@
 		}
 	}
 	if tag == "search" {
-		switch m := r.URL.Query().Get("m"); m {
-		case "symbol", "package", "vuln":
-			fmt.Println(tag, m)
-			tag += "-" + m
-		}
+		tag += "-" + searchMode(r)
 	}
 	return tag
 }
diff --git a/internal/frontend/server_test.go b/internal/frontend/server_test.go
index c5763bf..f156bc4 100644
--- a/internal/frontend/server_test.go
+++ b/internal/frontend/server_test.go
@@ -1504,7 +1504,7 @@
 		{"/search", mustRequest("http://localhost/search?q=net&m=vuln"), "search-vuln"},
 		{"/search", mustRequest("http://localhost/search?q=net&m=package"), "search-package"},
 		{"/search", mustRequest("http://localhost/search?q=net&m=symbol"), "search-symbol"},
-		{"/search", mustRequest("http://localhost/search?q=net"), "search"},
+		{"/search", mustRequest("http://localhost/search?q=net"), "search-package"},
 	}
 	for _, test := range tests {
 		t.Run(test.want, func(t *testing.T) {