[CT] Add desktop device when running run_benchmark

ct/go/worker_scripts/run_chromium_perf/main.go

Index: ct/go/worker_scripts/run_chromium_perf/main.go
diff --git a/ct/go/worker_scripts/run_chromium_perf/main.go b/ct/go/worker_scripts/run_chromium_perf/main.go
index 8ceea37a4b6372b526069a98fdb427e6b0b24a83..6797cc3074a078a03d1809c1b05a3bb75b18fa8b 100644
--- a/ct/go/worker_scripts/run_chromium_perf/main.go
+++ b/ct/go/worker_scripts/run_chromium_perf/main.go
@@ -305,7 +305,7 @@ func runBenchmark(fileInfoName, pathToPagesets, pathToPyFiles, localOutputDir, c
 	// Need to capture output for all benchmarks.
 	outputDirArgValue := filepath.Join(localOutputDir, pagesetName)
 	args = append(args, "--output-dir="+outputDirArgValue)
-	// Figure out which browser should be used.
+	// Figure out which browser and device should be used.
 	if *targetPlatform == util.PLATFORM_ANDROID {
 		if err := util.InstallChromeAPK(chromiumBuildName); err != nil {
 			return fmt.Errorf("Error while installing APK: %s", err)
@@ -313,12 +313,11 @@ func runBenchmark(fileInfoName, pathToPagesets, pathToPyFiles, localOutputDir, c
 		args = append(args, "--browser=android-chromium")
 	} else {
 		args = append(args, "--browser=exact", "--browser-executable="+chromiumBinary)
+		args = append(args, "--device=desktop")
 	}
 	// Split benchmark args if not empty and append to args.
 	if *benchmarkExtraArgs != "" {
-		for _, benchmarkArg := range strings.Fields(*benchmarkExtraArgs) {
-			args = append(args, benchmarkArg)
-		}
+		args = append(args, strings.Fields(*benchmarkExtraArgs)...)
 	}
 	// Add the number of times to repeat.
 	args = append(args, fmt.Sprintf("--page-repeat=%d", *repeatBenchmark))