diff --git a/cuj/cuj.go b/cuj/cuj.go
new file mode 100644
index 0000000..c7ff8ff
--- /dev/null
+++ b/cuj/cuj.go
@@ -0,0 +1,190 @@
+// Copyright 2019 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// This executable runs a series of build commands to test and benchmark some critical user journeys.
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+
+	"android/soong/ui/build"
+	"android/soong/ui/logger"
+	"android/soong/ui/metrics"
+	"android/soong/ui/status"
+	"android/soong/ui/terminal"
+	"android/soong/ui/tracer"
+)
+
+type Test struct {
+	name string
+	args []string
+
+	results TestResults
+}
+
+type TestResults struct {
+	metrics *metrics.Metrics
+	err     error
+}
+
+// Run runs a single build command.  It emulates the "m" command line by calling into Soong UI directly.
+func (t *Test) Run(logsDir string) {
+	output := terminal.NewStatusOutput(os.Stdout, "", false, false)
+
+	log := logger.New(output)
+	defer log.Cleanup()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	trace := tracer.New(log)
+	defer trace.Close()
+
+	met := metrics.New()
+
+	stat := &status.Status{}
+	defer stat.Finish()
+	stat.AddOutput(output)
+	stat.AddOutput(trace.StatusTracer())
+
+	build.SetupSignals(log, cancel, func() {
+		trace.Close()
+		log.Cleanup()
+		stat.Finish()
+	})
+
+	buildCtx := build.Context{ContextImpl: &build.ContextImpl{
+		Context: ctx,
+		Logger:  log,
+		Metrics: met,
+		Tracer:  trace,
+		Writer:  output,
+		Status:  stat,
+	}}
+
+	defer logger.Recover(func(err error) {
+		t.results.err = err
+	})
+
+	config := build.NewConfig(buildCtx, t.args...)
+	build.SetupOutDir(buildCtx, config)
+
+	os.MkdirAll(logsDir, 0777)
+	log.SetOutput(filepath.Join(logsDir, "soong.log"))
+	trace.SetOutput(filepath.Join(logsDir, "build.trace"))
+	stat.AddOutput(status.NewVerboseLog(log, filepath.Join(logsDir, "verbose.log")))
+	stat.AddOutput(status.NewErrorLog(log, filepath.Join(logsDir, "error.log")))
+	stat.AddOutput(status.NewProtoErrorLog(log, filepath.Join(logsDir, "build_error")))
+	stat.AddOutput(status.NewCriticalPath(log))
+
+	defer met.Dump(filepath.Join(logsDir, "soong_metrics"))
+
+	if start, ok := os.LookupEnv("TRACE_BEGIN_SOONG"); ok {
+		if !strings.HasSuffix(start, "N") {
+			if start_time, err := strconv.ParseUint(start, 10, 64); err == nil {
+				log.Verbosef("Took %dms to start up.",
+					time.Since(time.Unix(0, int64(start_time))).Nanoseconds()/time.Millisecond.Nanoseconds())
+				buildCtx.CompleteTrace(metrics.RunSetupTool, "startup", start_time, uint64(time.Now().UnixNano()))
+			}
+		}
+
+		if executable, err := os.Executable(); err == nil {
+			trace.ImportMicrofactoryLog(filepath.Join(filepath.Dir(executable), "."+filepath.Base(executable)+".trace"))
+		}
+	}
+
+	f := build.NewSourceFinder(buildCtx, config)
+	defer f.Shutdown()
+	build.FindSources(buildCtx, config, f)
+
+	build.Build(buildCtx, config, build.BuildAll)
+
+	t.results.metrics = met
+}
+
+func main() {
+	outDir := os.Getenv("OUT_DIR")
+	if outDir == "" {
+		outDir = "out"
+	}
+
+	cujDir := filepath.Join(outDir, "cuj_tests")
+
+	// Use a subdirectory for the out directory for the tests to keep them isolated.
+	os.Setenv("OUT_DIR", filepath.Join(cujDir, "out"))
+
+	// Each of these tests is run in sequence without resetting the output tree.  The state of the output tree will
+	// affect each successive test.  To maintain the validity of the benchmarks across changes, care must be taken
+	// to avoid changing the state of the tree when a test is run.  This is most easily accomplished by adding tests
+	// at the end.
+	tests := []Test{
+		{
+			// Reset the out directory to get reproducible results.
+			name: "clean",
+			args: []string{"clean"},
+		},
+		{
+			// Parse the build files.
+			name: "nothing",
+			args: []string{"nothing"},
+		},
+		{
+			// Parse the build files again to monitor issues like globs rerunning.
+			name: "nothing_rebuild",
+			args: []string{"nothing"},
+		},
+		{
+			// Parse the build files again, this should always be very short.
+			name: "nothing_rebuild_twice",
+			args: []string{"nothing"},
+		},
+		{
+			// Build the framework as a common developer task and one that keeps getting longer.
+			name: "framework",
+			args: []string{"framework"},
+		},
+		{
+			// Build the framework again to make sure it doesn't rebuild anything.
+			name: "framework_rebuild",
+			args: []string{"framework"},
+		},
+		{
+			// Build the framework again to make sure it doesn't rebuild anything even if it did the second time.
+			name: "framework_rebuild_twice",
+			args: []string{"framework"},
+		},
+	}
+
+	cujMetrics := metrics.NewCriticalUserJourneysMetrics()
+	defer cujMetrics.Dump(filepath.Join(cujDir, "logs", "cuj_metrics.pb"))
+
+	for i, t := range tests {
+		logsSubDir := fmt.Sprintf("%02d_%s", i, t.name)
+		logsDir := filepath.Join(cujDir, "logs", logsSubDir)
+		t.Run(logsDir)
+		if t.results.err != nil {
+			fmt.Printf("error running test %q: %s\n", t.name, t.results.err)
+			break
+		}
+		if t.results.metrics != nil {
+			cujMetrics.Add(t.name, t.results.metrics)
+		}
+	}
+}