Implement IntentFilter verification service.

This commit adds a verifier that verifies a host delegates permission for
an app to handle Url for the host using the Statement protocol.

- Implements the Statement protocol
-- The protocol defines a file format that represents statements.
-- The protocol defines where each asset type should put their statement
declaration. For web asset, the statement file should be hosted at
<scheme>://<host>:<port>/.well-known/associations.json.

- Implements IntentFilterVerificationReceiver, an interface between
StatementService and PackageManager. PackageManager will send a
broadcast with action Intent.ACTION_INTENT_FILTER_NEEDS_VERIFICATION.
The service will process the request and returns the results by calling
PackageManager.verifyIntentFilter().

To verify an IntentFilter like this defined in Android app com.test.app
<intent-filter>
  <data android:scheme="https" />
  <data android:host="www.test.com" />
  <data android:pathPattern=".*"/>
</intent-filter>

The service will try to retrieve the statement file from
https://www.test.com:443/.well-known/associations.json and try to find
a JSON object equivalent to
{'relation': ['delegate_permission/common.handle_all_urls'],
 'target': {'namespace': 'android_app',
            'package_name': 'com.test.app',
            'sha256_cert_fingerprints': [APP_CERT_FP]}}
The entry should have the correct relation, package name, and
certificate sha256 fingerprint.

Because this implementation will send a HTTP request for each host
specified in the intent-filter in AndroidManifest.xml, to avoid overwhelming
the network at app install time, we limit the maximum number of hosts we will
verify for a single app to 10. Any app with more than 10 hosts in the
autoVerify=true intent-filter won't be auto verified.

Change-Id: I787c9d176e4110aa441eb5fe4fa9651a071c6610
diff --git a/packages/StatementService/Android.mk b/packages/StatementService/Android.mk
new file mode 100644
index 0000000..f0adb1c
--- /dev/null
+++ b/packages/StatementService/Android.mk
@@ -0,0 +1,33 @@
+# Copyright (C) 2015 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.
+
+LOCAL_PATH:= $(call my-dir)
+include $(CLEAR_VARS)
+
+LOCAL_MODULE_TAGS := optional
+
+LOCAL_SRC_FILES := $(call all-java-files-under, src)
+
+LOCAL_PROGUARD_FLAG_FILES := proguard.flags
+
+LOCAL_PACKAGE_NAME := StatementService
+LOCAL_PRIVILEGED_MODULE := true
+
+LOCAL_STATIC_JAVA_LIBRARIES := \
+    libprotobuf-java-nano \
+    volley
+
+include $(BUILD_PACKAGE)
+
+include $(call all-makefiles-under,$(LOCAL_PATH)/src)