Add native interface for activity manager service.

Fix the un/marshalling code at
frameworks/av/media/libmediaplayerservice and move it here.

Bug: 30977067
Test: Verified that transaction works fine.

Change-Id: Ice6bd1c8ebc8116147b0ca3f65a293d013edfc4c
diff --git a/libs/binder/IActivityManager.cpp b/libs/binder/IActivityManager.cpp
new file mode 100644
index 0000000..898ee52
--- /dev/null
+++ b/libs/binder/IActivityManager.cpp
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2016 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 <binder/IActivityManager.h>
+
+#include <binder/Parcel.h>
+
+namespace android {
+
+// ------------------------------------------------------------------------------------
+
+class BpActivityManager : public BpInterface<IActivityManager>
+{
+public:
+    explicit BpActivityManager(const sp<IBinder>& impl)
+        : BpInterface<IActivityManager>(impl)
+    {
+    }
+
+    virtual int openContentUri(const String16& stringUri)
+    {
+        Parcel data, reply;
+        data.writeString16(stringUri);
+        status_t ret = remote()->transact(OPEN_CONTENT_URI_TRANSACTION, data, & reply);
+        int fd = -1;
+        if (ret == NO_ERROR) {
+            int32_t exceptionCode = reply.readExceptionCode();
+            if (!exceptionCode) {
+                // Success is indicated here by a nonzero int followed by the fd;
+                // failure by a zero int with no data following.
+                if (reply.readInt32() != 0) {
+                    fd = dup(reply.readParcelFileDescriptor());
+                }
+            } else {
+                // An exception was thrown back; fall through to return failure
+                ALOGD("openContentUri(%s) caught exception %d\n",
+                        String8(stringUri).string(), exceptionCode);
+            }
+        }
+        return fd;
+    }
+};
+
+// ------------------------------------------------------------------------------------
+
+IMPLEMENT_META_INTERFACE(ActivityManager, "android.app.IActivityManager");
+
+}; // namespace android