[CT] Add ability to run unlanded benchmarks on Chromium Perf

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 7282c4f602e31e597d860cacbe7adbac82035bc0..4dec26ed4a7b9b67652508c0829d8b69aad0fb69 100644
--- a/ct/go/worker_scripts/run_chromium_perf/main.go
+++ b/ct/go/worker_scripts/run_chromium_perf/main.go
@@ -6,6 +6,7 @@ import (
 	"encoding/csv"
 	"flag"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -34,6 +35,7 @@ var (
 	pagesetType               = flag.String("pageset_type", util.PAGESET_TYPE_MOBILE_10k, "The type of pagesets to create from the Alexa CSV list. Eg: 10k, Mobile10k, All.")
 	chromiumBuildNoPatch      = flag.String("chromium_build_nopatch", "", "The chromium build to use for the nopatch run.")
 	chromiumBuildWithPatch    = flag.String("chromium_build_withpatch", "", "The chromium build to use for the withpatch run.")
+	runID                     = flag.String("run_id", "", "The unique run id (typically requester + timestamp).")
 	runIDNoPatch              = flag.String("run_id_nopatch", "", "The unique run id (typically requester + timestamp) for the nopatch run.")
 	runIDWithPatch            = flag.String("run_id_withpatch", "", "The unique run id (typically requester + timestamp) for the withpatch run.")
 	benchmarkName             = flag.String("benchmark_name", "", "The telemetry benchmark to run on this worker.")
@@ -113,6 +115,38 @@ func main() {
 		return
 	}
 
+	// Download the benchmark patch for this run from Google storage.
+	benchmarkPatchName := *runID + ".benchmark.patch"
+	benchmarkPatchLocalPath := filepath.Join(os.TempDir(), benchmarkPatchName)
+	remoteDir := filepath.Join(util.ChromiumPerfRunsDir, *runID)
+	benchmarkPatchRemotePath := filepath.Join(remoteDir, benchmarkPatchName)
+	respBody, err := gs.GetRemoteFileContents(benchmarkPatchRemotePath)
+	if err != nil {
+		glog.Errorf("Could not fetch %s: %s", benchmarkPatchRemotePath, err)
+		return
+	}
+	defer skutil.Close(respBody)
+	out, err := os.Create(benchmarkPatchLocalPath)

[dogben, 2015/10/20 15:17:26]

Seems like you could use os.WriteFile.
https://golang.org/pkg/io/ioutil/#WriteFile

[rmistry, 2015/10/20 17:47:48]

Done.

+	if err != nil {
+		glog.Errorf("Unable to create file %s: %s", benchmarkPatchLocalPath, err)
+		return
+	}
+	defer skutil.Close(out)
+	defer skutil.Remove(benchmarkPatchLocalPath)
+	if _, err = io.Copy(out, respBody); err != nil {
+		glog.Error(err)
+		return
+	}
+	// Apply benchmark patch to the local chromium checkout.
+	benchmarkPatchFile, _ := os.Open(benchmarkPatchLocalPath)

[dogben, 2015/10/20 15:17:26]

Use os.Stat. https://golang.org/pkg/os/#Stat
(Or defer skutil.Close(benchmarkPatchFile))

[rmistry, 2015/10/20 17:47:48]

Done.

[dogben, 2015/10/20 18:14:08]

Nit: You actually have the size from buf above, so Stat is not really needed.

[rmistry, 2015/10/21 12:32:47]

Done.

+	benchmarkPatchFileInfo, _ := benchmarkPatchFile.Stat()
+	if benchmarkPatchFileInfo.Size() > 10 {
+		if err := util.ApplyPatch(benchmarkPatchLocalPath, util.ChromiumSrcDir); err != nil {
+			glog.Errorf("Could not apply Telemetry's patch in %s: %s", util.ChromiumSrcDir, err)
+			return
+		}
+	}
+
 	// Download the specified chromium builds.
 	for _, chromiumBuild := range []string{*chromiumBuildNoPatch, *chromiumBuildWithPatch} {
 		if err := gs.DownloadChromiumBuild(chromiumBuild); err != nil {
@@ -253,9 +287,14 @@ func runBenchmark(fileInfoName, pathToPagesets, pathToPyFiles, localOutputDir, c
 	}
 
 	glog.Infof("===== Processing %s for %s =====", pagesetPath, runID)
+	pagesetName, present := util.BenchmarksToPagesetName[*benchmarkName]
+	if !present {
+		// If it is custom benchmark use the entered benchmark name.
+		pagesetName = *benchmarkName
+	}
 	args := []string{
 		filepath.Join(util.TelemetryBinariesDir, util.BINARY_RUN_BENCHMARK),
-		util.BenchmarksToPagesetName[*benchmarkName],
+		pagesetName,
 		"--also-run-disabled-tests",
 		"--user-agent=" + decodedPageset.UserAgent,
 		"--urls-list=" + decodedPageset.UrlsList,