Don't record audio if UID is idle - native framework

If a UID is in an idle state we don't allow recording to protect
user's privacy. If the UID is in an idle state we allow recording
but report empty data (all zeros in the byte array) and once
the process goes in an active state we report the real mic data.
This avoids the race between the app being notified aboout its
lifecycle and the audio system being notified about the state
of a UID.

Test: Added - AudioRecordTest#testRecordNoDataForIdleUids
      Passing - cts-tradefed run cts-dev -m CtsMediaTestCases
                        -t android.media.cts.AudioRecordTest

bug:63938985

Change-Id: I10db89c09498b487ce483d1868123fca95589b34
diff --git a/libs/binder/ActivityManager.cpp b/libs/binder/ActivityManager.cpp
new file mode 100644
index 0000000..2904718
--- /dev/null
+++ b/libs/binder/ActivityManager.cpp
@@ -0,0 +1,81 @@
+/*
+ * 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.
+ */
+
+#include <mutex>
+#include <binder/ActivityManager.h>
+#include <binder/Binder.h>
+#include <binder/IServiceManager.h>
+
+#include <utils/SystemClock.h>
+
+namespace android {
+
+ActivityManager::ActivityManager()
+{
+}
+
+sp<IActivityManager> ActivityManager::getService()
+{
+    std::lock_guard<Mutex> scoped_lock(mLock);
+    int64_t startTime = 0;
+    sp<IActivityManager> service = mService;
+    while (service == NULL || !IInterface::asBinder(service)->isBinderAlive()) {
+        sp<IBinder> binder = defaultServiceManager()->checkService(String16("activity"));
+        if (binder == NULL) {
+            // Wait for the activity service to come back...
+            if (startTime == 0) {
+                startTime = uptimeMillis();
+                ALOGI("Waiting for activity service");
+            } else if ((uptimeMillis() - startTime) > 10000) {
+                ALOGW("Waiting too long for activity service, giving up");
+                service = NULL;
+                break;
+            }
+            sleep(1);
+        } else {
+            service = interface_cast<IActivityManager>(binder);
+            mService = service;
+        }
+    }
+    return service;
+}
+
+int ActivityManager::openContentUri(const String16& stringUri)
+{
+    sp<IActivityManager> service = getService();
+    return service != NULL ? service->openContentUri(stringUri) : -1;
+}
+
+void ActivityManager::registerUidObserver(const sp<IUidObserver>& observer,
+                                          const int32_t event,
+                                          const int32_t cutpoint,
+                                          const String16& callingPackage)
+{
+    sp<IActivityManager> service = getService();
+    if (service != NULL) {
+        service->registerUidObserver(observer, event, cutpoint, callingPackage);
+    }
+}
+
+void ActivityManager::unregisterUidObserver(const sp<IUidObserver>& observer)
+{
+    sp<IActivityManager> service = getService();
+    if (service != NULL) {
+        service->unregisterUidObserver(observer);
+    }
+}
+
+}; // namespace android