Support for install multiple boot images.

Bug: 119800099
Test: m && /system/framework/arm/apex*.art files exist
Change-Id: I8b708a0c495193e5455e03eaa575ce55a482a95d
diff --git a/dexpreopt/config.go b/dexpreopt/config.go
index 9981401..15008b9 100644
--- a/dexpreopt/config.go
+++ b/dexpreopt/config.go
@@ -31,6 +31,8 @@
 
 	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
+
 	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