Add a library for running external commands, providing timeouts and test injection.

ct/go/adb/adb.go

 // Utility that contains utility methods for interacting with adb.
 package adb
 
 import (
         "fmt"
         "os/exec"
         "time"
 
-        "github.com/skia-dev/glog"
-
         "go.skia.org/infra/ct/go/util"
+        skexec "go.skia.org/infra/go/exec"
         skutil "go.skia.org/infra/go/util"
 )
 
 // VerifyLocalDevice does not throw an error if an Android device is connected and
 // online. An error is returned if either "adb" is not installed or if the Android
 // device is offline or missing.
 func VerifyLocalDevice() error {
         // Run "adb version".
         // Command should return without an error.
         if err := util.ExecuteCmd(util.BINARY_ADB, []string{"version"}, []string{}, 5*time.Minute, nil, nil); err != nil {
                 return fmt.Errorf("adb not installed or not found: %s", err)
         }
 
         // Run "adb devices | grep offline".
         // Command should return with an error.
         devicesCmd := exec.Command(util.BINARY_ADB, "devices")
         offlineCmd := exec.Command("grep", "offline")
         offlineCmd.Stdin, _ = devicesCmd.StdoutPipe()
-        offlineCmd.Stdout = util.WriteLog{LogFunc: glog.Infof, OutputFile: nil}
+        offlineCmd.Stdout = skexec.WriteInfoLog
         skutil.LogErr(offlineCmd.Start())
         skutil.LogErr(devicesCmd.Run())
         if err := offlineCmd.Wait(); err == nil {
                 // A nil error here means that an offline device was found.
                 return fmt.Errorf("Android device is offline: %s", err)
         }
 
         // Running "adb devices | grep device$
         // Command should return without an error.
         devicesCmd = exec.Command(util.BINARY_ADB, "devices")
         missingCmd := exec.Command("grep", "device$")
         missingCmd.Stdin, _ = devicesCmd.StdoutPipe()
-        missingCmd.Stdout = util.WriteLog{LogFunc: glog.Infof, OutputFile: nil}
+        missingCmd.Stdout = skexec.WriteInfoLog
         skutil.LogErr(missingCmd.Start())
         skutil.LogErr(devicesCmd.Run())
         if err := missingCmd.Wait(); err != nil {
                 // An error here means that the device is missing.
                 return fmt.Errorf("Android device is missing: %s", err)
         }
 
         return nil
 }