Allow using updatable boot jars in dexpreopt (but don't use them yet).

This CL handles updatable boot jars in the same hacky way as we handle
non-updatable boot jars: it creates a set of predefined paths to the dex
jars in a global config, then traverses all modules in a singleton
context, finds updatable boot jars and adds copy rules from these jars
to the predefined paths. A proper way would be to register dependencies
of the dexpreopted modules on the boot jars and extracting paths to dex
files by walking these dependencies.

Bug: 178467404
Test: lunch aosp_cf_x86_64_phone-userdebug && m
Test: added new Soong test
Change-Id: I87f764109315f79315d73bf43799b70eb010fc0b
diff --git a/java/dexpreopt.go b/java/dexpreopt.go
index a2961c2..b4cf012 100644
--- a/java/dexpreopt.go
+++ b/java/dexpreopt.go
@@ -160,14 +160,17 @@
 
 	globalSoong := dexpreopt.GetGlobalSoongConfig(ctx)
 	global := dexpreopt.GetGlobalConfig(ctx)
+
+	isSystemServerJar := inList(ctx.ModuleName(), global.SystemServerJars)
+
 	bootImage := defaultBootImageConfig(ctx)
-	dexFiles := bootImage.dexPathsDeps.Paths()
-	// The dex locations for all Android variants are identical.
-	dexLocations := bootImage.getAnyAndroidVariant().dexLocationsDeps
 	if global.UseArtImage {
 		bootImage = artBootImageConfig(ctx)
 	}
 
+	// System server jars are an exception: they are dexpreopted without updatable bootclasspath.
+	dexFiles, dexLocations := bcpForDexpreopt(ctx, global.PreoptWithUpdatableBcp && !isSystemServerJar)
+
 	targets := ctx.MultiTargets()
 	if len(targets) == 0 {
 		// assume this is a java library, dexpreopt for all arches for now
@@ -176,7 +179,7 @@
 				targets = append(targets, target)
 			}
 		}
-		if inList(ctx.ModuleName(), global.SystemServerJars) && !d.isSDKLibrary {
+		if isSystemServerJar && !d.isSDKLibrary {
 			// If the module is not an SDK library and it's a system server jar, only preopt the primary arch.
 			targets = targets[:1]
 		}
@@ -237,7 +240,7 @@
 		DexPreoptImagesDeps:     imagesDeps,
 		DexPreoptImageLocations: imageLocations,
 
-		PreoptBootClassPathDexFiles:     dexFiles,
+		PreoptBootClassPathDexFiles:     dexFiles.Paths(),
 		PreoptBootClassPathDexLocations: dexLocations,
 
 		PreoptExtractedApk: false,