Support non-installable java libraries

Some java libraries will never be installed, support an
installable: false property and export it back to make as
LOCAL_UNINSTALLABLE_MODULE := true.

Test: m -j checkbuild, manually inspect out/soong/Android*.mk
Change-Id: I825ec897648c82fb7323da7df3539c9aaa6bcfce
diff --git a/java/java.go b/java/java.go
index a8093e7..7b213b2 100644
--- a/java/java.go
+++ b/java/java.go
@@ -96,6 +96,9 @@
 
 	// If not blank, set the java version passed to javac as -source and -target
 	Java_version *string
+
+	// If set to false, don't allow this module to be installed.  Defaults to true.
+	Installable *bool
 }
 
 type CompilerDeviceProperties struct {
@@ -473,7 +476,10 @@
 func (j *Library) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	j.compile(ctx)
 
-	j.installFile = ctx.InstallFile(android.PathForModuleInstall(ctx, "framework"), ctx.ModuleName()+".jar", j.outputFile)
+	if j.properties.Installable == nil || *j.properties.Installable == true {
+		j.installFile = ctx.InstallFile(android.PathForModuleInstall(ctx, "framework"),
+			ctx.ModuleName()+".jar", j.outputFile)
+	}
 }
 
 func (j *Library) DepsMutator(ctx android.BottomUpMutatorContext) {
@@ -605,9 +611,6 @@
 	}
 
 	j.combinedClasspathFile = TransformClassesToJar(ctx, j.classJarSpecs, android.OptionalPath{}, nil)
-
-	ctx.InstallFile(android.PathForModuleInstall(ctx, "framework"),
-		ctx.ModuleName()+".jar", j.combinedClasspathFile)
 }
 
 var _ Dependency = (*Import)(nil)