Move Ethernet related files to f/b/packages/ConnectivityT.

ethernet-service is going to be moved into Connectivity mainline module.
Notice that below sources are also only used in the ethernet framework
during compiling the filegroup: framework-connectivity-ethernet-sources.
Move them from f/b to f/b/packages/ConnectivityT as well.

Ethernet framework only related files:
    - IInternalNetworkManagementListener.aidl
    - InternalNetworkManagementException.java
    - InternalNetworkManagementException.aidl
    - InternalNetworkUpdateRequest.java
    - InternalNetworkUpdateRequest.aidl

Ethernet service only related files:
    - DelayedDiskWrite.java(IpConfigStore imports this class)

Bug: 210586283
Test: build pass
      atest FrameworksNetTests
      atest EthernetServiceTests
Change-Id: I1ec2d1d182c04f3f2acc9b757d5061ca749a4a3c

service-t/Sources.bp

@@ -66,6 +66,7 @@ filegroup {
 filegroup {
     name: "services.connectivity-ethernet-sources",
     srcs: [
+        "src/com/android/server/net/DelayedDiskWrite.java",
         "src/com/android/server/net/IpConfigStore.java",
     ],
     path: "src",

service-t/src/com/android/server/net/DelayedDiskWrite.java

@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2014 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.
+ */
+
+package com.android.server.net;
+
+import android.os.Handler;
+import android.os.HandlerThread;
+import android.text.TextUtils;
+import android.util.Log;
+
+import java.io.BufferedOutputStream;
+import java.io.DataOutputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+
+/**
+ * This class provides APIs to do a delayed data write to a given {@link OutputStream}.
+ */
+public class DelayedDiskWrite {
+    private static final String TAG = "DelayedDiskWrite";
+
+    private HandlerThread mDiskWriteHandlerThread;
+    private Handler mDiskWriteHandler;
+    /* Tracks multiple writes on the same thread */
+    private int mWriteSequence = 0;
+
+    /**
+     * Used to do a delayed data write to a given {@link OutputStream}.
+     */
+    public interface Writer {
+        /**
+         * write data to a given {@link OutputStream}.
+         */
+        void onWriteCalled(DataOutputStream out) throws IOException;
+    }
+
+    /**
+     * Do a delayed data write to a given output stream opened from filePath.
+     */
+    public void write(final String filePath, final Writer w) {
+        write(filePath, w, true);
+    }
+
+    /**
+     * Do a delayed data write to a given output stream opened from filePath.
+     */
+    public void write(final String filePath, final Writer w, final boolean open) {
+        if (TextUtils.isEmpty(filePath)) {
+            throw new IllegalArgumentException("empty file path");
+        }
+
+        /* Do a delayed write to disk on a separate handler thread */
+        synchronized (this) {
+            if (++mWriteSequence == 1) {
+                mDiskWriteHandlerThread = new HandlerThread("DelayedDiskWriteThread");
+                mDiskWriteHandlerThread.start();
+                mDiskWriteHandler = new Handler(mDiskWriteHandlerThread.getLooper());
+            }
+        }
+
+        mDiskWriteHandler.post(new Runnable() {
+            @Override
+            public void run() {
+                doWrite(filePath, w, open);
+            }
+        });
+    }
+
+    private void doWrite(String filePath, Writer w, boolean open) {
+        DataOutputStream out = null;
+        try {
+            if (open) {
+                out = new DataOutputStream(new BufferedOutputStream(
+                        new FileOutputStream(filePath)));
+            }
+            w.onWriteCalled(out);
+        } catch (IOException e) {
+            loge("Error writing data file " + filePath);
+        } finally {
+            if (out != null) {
+                try {
+                    out.close();
+                } catch (Exception e) { }
+            }
+
+            // Quit if no more writes sent
+            synchronized (this) {
+                if (--mWriteSequence == 0) {
+                    mDiskWriteHandler.getLooper().quit();
+                    mDiskWriteHandler = null;
+                    mDiskWriteHandlerThread = null;
+                }
+            }
+        }
+    }
+
+    private void loge(String s) {
+        Log.e(TAG, s);
+    }
+}
+