support toggling compare mode for rbe actions

This allows me to set metalava actions to run remotely (already toggleable) with local comparison (this CL).

Change-Id: I66b006d5ee11b3192ef81a2e5cefc07e9f3d10a2

java/droidstubs.go

@@ -19,6 +19,7 @@ import (
 	"path/filepath"
 	"regexp"
 	"sort"
+	"strconv"
 	"strings"
 
 	"github.com/google/blueprint/proptools"
@@ -497,6 +498,7 @@ func metalavaCmd(ctx android.ModuleContext, rule *android.RuleBuilder, javaVersi
 	if metalavaUseRbe(ctx) {
 		rule.Remoteable(android.RemoteRuleSupports{RBE: true})
 		execStrategy := ctx.Config().GetenvWithDefault("RBE_METALAVA_EXEC_STRATEGY", remoteexec.LocalExecStrategy)
+		compare, _ := strconv.ParseBool(ctx.Config().GetenvWithDefault("RBE_METALAVA_COMPARE", "false"))
 		labels := map[string]string{"type": "tool", "name": "metalava"}
 		// TODO: metalava pool rejects these jobs
 		pool := ctx.Config().GetenvWithDefault("RBE_METALAVA_POOL", "java16")
@@ -505,6 +507,9 @@ func metalavaCmd(ctx android.ModuleContext, rule *android.RuleBuilder, javaVersi
 			ExecStrategy:    execStrategy,
 			ToolchainInputs: []string{config.JavaCmd(ctx).String()},
 			Platform:        map[string]string{remoteexec.PoolKey: pool},
+			Compare:         compare,
+			NumLocalRuns:    1,
+			NumRemoteRuns:   1,
 		})
 	}