Add a prod var to override package names.

Currently only java/app.go is affected by package name overrides. When
the var is used, the corresponding module's install APK name is changed
to the overriding name.

Bug: 122957760
Test: app_test.go + TreeHugger
Change-Id: Ie522da3d7280970d740d779cf2694560feae6180
diff --git a/java/app.go b/java/app.go
index 45ef489..cc863e6 100644
--- a/java/app.go
+++ b/java/app.go
@@ -82,6 +82,9 @@
 	installJniLibs []jniLib
 
 	bundleFile android.Path
+
+	// the install APK name is normally the same as the module name, but can be overridden with PRODUCT_PACKAGE_NAME_OVERRIDES.
+	installApkName string
 }
 
 func (a *AndroidApp) ExportedProguardFlagFiles() android.Paths {
@@ -215,11 +218,11 @@
 		// framework-res.apk is installed as system/framework/framework-res.apk
 		installDir = "framework"
 	} else if Bool(a.appProperties.Privileged) {
-		installDir = filepath.Join("priv-app", ctx.ModuleName())
+		installDir = filepath.Join("priv-app", a.installApkName)
 	} else {
-		installDir = filepath.Join("app", ctx.ModuleName())
+		installDir = filepath.Join("app", a.installApkName)
 	}
-	a.dexpreopter.installPath = android.PathForModuleInstall(ctx, installDir, ctx.ModuleName()+".apk")
+	a.dexpreopter.installPath = android.PathForModuleInstall(ctx, installDir, a.installApkName+".apk")
 
 	if ctx.ModuleName() != "framework-res" {
 		a.Module.compile(ctx, a.aaptSrcJar)
@@ -276,6 +279,9 @@
 }
 
 func (a *AndroidApp) generateAndroidBuildActions(ctx android.ModuleContext) {
+	// Check if the install APK name needs to be overridden.
+	a.installApkName = ctx.DeviceConfig().OverridePackageNameFor(ctx.ModuleName())
+
 	// Process all building blocks, from AAPT to certificates.
 	a.aaptBuildActions(ctx)
 
@@ -307,9 +313,9 @@
 		// framework-res.apk is installed as system/framework/framework-res.apk
 		ctx.InstallFile(android.PathForModuleInstall(ctx, "framework"), ctx.ModuleName()+".apk", a.outputFile)
 	} else if Bool(a.appProperties.Privileged) {
-		ctx.InstallFile(android.PathForModuleInstall(ctx, "priv-app", ctx.ModuleName()), ctx.ModuleName()+".apk", a.outputFile)
+		ctx.InstallFile(android.PathForModuleInstall(ctx, "priv-app", a.installApkName), a.installApkName+".apk", a.outputFile)
 	} else {
-		ctx.InstallFile(android.PathForModuleInstall(ctx, "app", ctx.ModuleName()), ctx.ModuleName()+".apk", a.outputFile)
+		ctx.InstallFile(android.PathForModuleInstall(ctx, "app", a.installApkName), a.installApkName+".apk", a.outputFile)
 	}
 }
 
diff --git a/java/app_test.go b/java/app_test.go
index 9d7ed0a..7e06dba 100644
--- a/java/app_test.go
+++ b/java/app_test.go
@@ -530,3 +530,66 @@
 		})
 	}
 }
+
+func TestPackageNameOverride(t *testing.T) {
+	testCases := []struct {
+		name                string
+		bp                  string
+		packageNameOverride string
+		expected            []string
+	}{
+		{
+			name: "default",
+			bp: `
+				android_app {
+					name: "foo",
+					srcs: ["a.java"],
+				}
+			`,
+			packageNameOverride: "",
+			expected: []string{
+				buildDir + "/.intermediates/foo/android_common/foo.apk",
+				buildDir + "/target/product/test_device/system/app/foo/foo.apk",
+			},
+		},
+		{
+			name: "overridden",
+			bp: `
+				android_app {
+					name: "foo",
+					srcs: ["a.java"],
+				}
+			`,
+			packageNameOverride: "foo:bar",
+			expected: []string{
+				// The package apk should be still be the original name for test dependencies.
+				buildDir + "/.intermediates/foo/android_common/foo.apk",
+				buildDir + "/target/product/test_device/system/app/bar/bar.apk",
+			},
+		},
+	}
+
+	for _, test := range testCases {
+		t.Run(test.name, func(t *testing.T) {
+			config := testConfig(nil)
+			if test.packageNameOverride != "" {
+				config.TestProductVariables.PackageNameOverrides = []string{test.packageNameOverride}
+			}
+			ctx := testAppContext(config, test.bp, nil)
+
+			run(t, ctx, config)
+			foo := ctx.ModuleForTests("foo", "android_common")
+
+			outputs := foo.AllOutputs()
+			outputMap := make(map[string]bool)
+			for _, o := range outputs {
+				outputMap[o] = true
+			}
+			for _, e := range test.expected {
+				if _, exist := outputMap[e]; !exist {
+					t.Errorf("Can't find %q in output files.\nAll outputs:%v", e, outputs)
+				}
+			}
+		})
+	}
+}