Modularize logd.

Separates logd body into a static library liblogd and
virtualize LogBuffer::log to be in a new interface class
LogBufferInterface. User could have different implementation.

Bug: 37756450
Test: liblog-unit-tests, logd-unit-tests and logcat-unit-tests
with (b/37791296).
Change-Id: I1504ff0e992744001b5a2e9abd45692d1318a152
diff --git a/logd/LogBufferInterface.cpp b/logd/LogBufferInterface.cpp
new file mode 100644
index 0000000..3cb2b89
--- /dev/null
+++ b/logd/LogBufferInterface.cpp
@@ -0,0 +1,22 @@
+/*
+ * 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 "LogBufferInterface.h"
+
+LogBufferInterface::LogBufferInterface() {
+}
+LogBufferInterface::~LogBufferInterface() {
+}
\ No newline at end of file