DevicePolicyManager: Add key generation functionality.

This is the crux of the Verified Access feature implementation:
Adding the ability to generate KeyChain keys directly by the
secure hardware, rather than installing software-generated keys
into KeyChain.

Add generateKeyPair to the DevicePolicyManager, which delegates key
generation (via the DevicePolicyManagerService) to the KeyChainService.

Design highlights:
* The key generation is delegated via the DevicePolicyManagerService to
  check that only authorized callers request key generation in KeyChain.
* KeyChainService performs the actual key generation so it owns the key
  in Keystore outright.
* DevicePolicyManagerService then grants the calling app access to the
  Keystore key, so it can actually be used.
* Loading the public/private key pair, as well as attestation
  certificate chain, is done in the client code (DevicePolicyManager)
  to save parceling / unparceling those objects across process
  boundaries twice (for no good reason).

NOTE: The key attestation functionality (that includes Device ID) is
missing/untested. Will be added in a follow-up CL as this one is quite
big already.

HIGHLIGHT FOR REVIEWERS:
* API: New API in DevicePolicyManager.

Bug: 63388672
Test: cts-tradefed run commandAndExit cts-dev -a armeabi-v7a -m CtsDevicePolicyManagerTestCases -t com.android.cts.devicepolicy.DeviceOwnerTest#testKeyManagement -l DEBUG; adb shell am instrument 'android.security.tests/android.support.test.runner.AndroidJUnitRunner' (After building the KeystoreTests target and installing the apk)
Change-Id: I73762c9123f32a94d454ba4f8b533883b55c44cc
diff --git a/keystore/tests/AndroidManifest.xml b/keystore/tests/AndroidManifest.xml
new file mode 100644
index 0000000..9bf2d0c
--- /dev/null
+++ b/keystore/tests/AndroidManifest.xml
@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2017 The Android Open Source Project
+
+     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.
+-->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="android.security.tests">
+
+    <application>
+        <uses-library android:name="android.test.runner" />
+    </application>
+
+    <instrumentation android:name="android.support.test.runner.AndroidJUnitRunner"
+        android:targetPackage="android.security.tests"
+        android:label="Tests for Keystore">
+    </instrumentation>
+</manifest>
+