diff --git a/android/apex.go b/android/apex.go
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--- /dev/null
+++ b/android/apex.go
@@ -0,0 +1,102 @@
+// Copyright 2018 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package android
+
+// ApexModule is the interface that a module type is expected to implement if
+// the module has to be built differently depending on whether the module
+// is destined for an apex or not (installed to one of the regular partitions).
+//
+// Native shared libraries are one such module type; when it is built for an
+// APEX, it should depend only on stable interfaces such as NDK, stable AIDL,
+// or C APIs from other APEXs.
+//
+// A module implementing this interface will be mutated into multiple
+// variations by the apex mutator if it is directly or indirectly included
+// in one or more APEXs. Specifically, if a module is included in apex.foo and
+// apex.bar then three apex variants are created: platform, apex.foo and
+// apex.bar. The platform variant is for the regular partitions
+// (e.g., /system or /vendor, etc.) while the other two are for the APEXs,
+// respectively.
+type ApexModule interface {
+	Module
+	apexModuleBase() *ApexModuleBase
+
+	// Marks that this module should be built for the APEX of the specified name
+	BuildForApex(apexName string)
+
+	// Tests whether this module will be built for the platform or not (= APEXs)
+	IsForPlatform() bool
+
+	// Returns the name of APEX that this module will be built for. Empty string
+	// is returned when 'IsForPlatform() == true'. Note that a module can be
+	// included to multiple APEXs, in which case, the module is mutated into
+	// multiple modules each of which for an APEX. This method returns the
+	// name of the APEX that a variant module is for.
+	ApexName() string
+
+	// Tests if this module can have APEX variants. APEX variants are
+	// created only for the modules that returns true here. This is useful
+	// for not creating APEX variants for shared libraries such as NDK stubs.
+	CanHaveApexVariants() bool
+
+	// Tests if this module can be installed to APEX as a file. For example,
+	// this would return true for shared libs while return false for static
+	// libs.
+	IsInstallableToApex() bool
+}
+
+type ApexProperties struct {
+	ApexName string `blueprint:"mutated"`
+}
+
+// Provides default implementation for the ApexModule interface. APEX-aware
+// modules are expected to include this struct and call InitApexModule().
+type ApexModuleBase struct {
+	ApexProperties ApexProperties
+
+	canHaveApexVariants bool
+}
+
+func (m *ApexModuleBase) apexModuleBase() *ApexModuleBase {
+	return m
+}
+
+func (m *ApexModuleBase) BuildForApex(apexName string) {
+	m.ApexProperties.ApexName = apexName
+}
+
+func (m *ApexModuleBase) IsForPlatform() bool {
+	return m.ApexProperties.ApexName == ""
+}
+
+func (m *ApexModuleBase) ApexName() string {
+	return m.ApexProperties.ApexName
+}
+
+func (m *ApexModuleBase) CanHaveApexVariants() bool {
+	return m.canHaveApexVariants
+}
+
+func (m *ApexModuleBase) IsInstallableToApex() bool {
+	// should be overriden if needed
+	return false
+}
+
+func InitApexModule(m ApexModule) {
+	base := m.apexModuleBase()
+	base.canHaveApexVariants = true
+
+	m.AddProperties(&base.ApexProperties)
+}