Add override_module.

This new module type replaces the inherit-package function in make by
allowing developers to override the name, the certificate, and the
manifest package name of an android_app module.

Bug: 122957760
Fixes: 123640028
Test: app_test.go + BrowserGoogle
Change-Id: Iefe447e7078b25039233221361ef95c83a29973a

java/app_test.go

@@ -747,3 +747,57 @@ func TestPackageNameOverride(t *testing.T) {
 		})
 	}
 }
+
+func TestOverrideModule(t *testing.T) {
+	ctx := testJava(t, `
+		android_app {
+			name: "foo",
+			srcs: ["a.java"],
+		}
+
+		override_module {
+			name: "bar",
+			base: "foo",
+			certificate: ":new_certificate",
+			manifest_package_name: "org.dandroid.bp",
+		}
+
+		android_app_certificate {
+			name: "new_certificate",
+	    certificate: "cert/new_cert",
+		}
+		`)
+
+	// The base module still contains all the final outputs after overrides.
+	foo := ctx.ModuleForTests("foo", "android_common")
+
+	// Check the final apk name
+	outputs := foo.AllOutputs()
+	e := buildDir + "/target/product/test_device/system/app/bar/bar.apk"
+	found := false
+	for _, o := range outputs {
+		if o == e {
+			found = true
+			break
+		}
+	}
+	if !found {
+		t.Errorf("Can't find %q in output files.\nAll outputs:%v", e, outputs)
+	}
+
+	// Check the certificate paths
+	signapk := foo.Output("foo.apk")
+	signFlags := signapk.Args["certificates"]
+	e = "cert/new_cert.x509.pem cert/new_cert.pk8"
+	if e != signFlags {
+		t.Errorf("Incorrect signing flags, expected: %q, got: %q", e, signFlags)
+	}
+
+	// Check the manifest package name
+	res := foo.Output("package-res.apk")
+	aapt2Flags := res.Args["flags"]
+	e = "--rename-manifest-package org.dandroid.bp"
+	if !strings.Contains(aapt2Flags, e) {
+		t.Errorf("package renaming flag, %q is missing in aapt2 link flags, %q", e, aapt2Flags)
+	}
+}