Use the apex image when the device config asks for it.

Test: lunch walleye_jitzygote-userdebug m && all odex file use the apex image
Bug: 119800099
Change-Id: Id2fff6a4569d48b8e6a886cb82bdba205b0dd56a

dexpreopt/config.go

@@ -32,6 +32,7 @@ type GlobalConfig struct {
 	OnlyPreoptBootImageAndSystemServer bool // only preopt jars in the boot image or system server
 
 	GenerateApexImage bool // generate an extra boot image only containing jars from the runtime apex
+	UseApexImage      bool // use the apex image by default
 
 	HasSystemOther        bool     // store odex files that match PatternsOnSystemOther on the system_other partition
 	PatternsOnSystemOther []string // patterns (using '%' to denote a prefix match) to put odex on the system_other partition

java/dexpreopt.go

@@ -98,6 +98,9 @@ func (d *dexpreopter) dexpreopt(ctx android.ModuleContext, dexJarFile android.Mo
 
 	global := dexpreoptGlobalConfig(ctx)
 	bootImage := defaultBootImageConfig(ctx)
+	if global.UseApexImage {
+		bootImage = apexBootImageConfig(ctx)
+	}
 
 	var archs []android.ArchType
 	for _, a := range ctx.MultiTargets() {