Add set-mode command to turn battery saver mode on and off.

Affected test will be modified in ag/2101279

Test: adb shell cmd battery unplug && adb shell cmd power set-mode 0
Bug: 31944272
Change-Id: Ia88e7e164aa9b8b4d0ab51f607a64b35e2159273

services/core/java/com/android/server/power/PowerManagerService.java

@@ -46,6 +46,8 @@ import android.os.PowerManagerInternal;
 import android.os.PowerSaveState;
 import android.os.Process;
 import android.os.RemoteException;
+import android.os.ResultReceiver;
+import android.os.ShellCallback;
 import android.os.SystemClock;
 import android.os.SystemProperties;
 import android.os.Trace;
@@ -4027,6 +4029,14 @@ public final class PowerManagerService extends SystemService
     }
 
     private final class BinderService extends IPowerManager.Stub {
+        @Override
+        public void onShellCommand(FileDescriptor in, FileDescriptor out,
+                FileDescriptor err, String[] args, ShellCallback callback,
+                ResultReceiver resultReceiver) {
+            (new PowerManagerShellCommand(this)).exec(
+                    this, in, out, err, args, callback, resultReceiver);
+        }
+
         @Override // Binder call
         public void acquireWakeLockWithUid(IBinder lock, int flags, String tag,
                 String packageName, int uid) {

services/core/java/com/android/server/power/PowerManagerShellCommand.java

@@ -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.
+ */
+
+package com.android.server.power;
+
+import android.content.Intent;
+import android.os.IPowerManager;
+import android.os.RemoteException;
+import android.os.ShellCommand;
+
+import java.io.PrintWriter;
+
+class PowerManagerShellCommand extends ShellCommand {
+    private static final int LOW_POWER_MODE_ON = 1;
+
+    final IPowerManager mInterface;
+
+    PowerManagerShellCommand(IPowerManager service) {
+        mInterface = service;
+    }
+
+    @Override
+    public int onCommand(String cmd) {
+        if (cmd == null) {
+            return handleDefaultCommands(cmd);
+        }
+
+        final PrintWriter pw = getOutPrintWriter();
+        try {
+            switch(cmd) {
+                case "set-mode":
+                    return runSetMode();
+                default:
+                    return handleDefaultCommands(cmd);
+            }
+        } catch (RemoteException e) {
+            pw.println("Remote exception: " + e);
+        }
+        return -1;
+    }
+
+    private int runSetMode() throws RemoteException {
+        final PrintWriter pw = getOutPrintWriter();
+        int mode = -1;
+        try {
+            mode = Integer.parseInt(getNextArgRequired());
+        } catch (RuntimeException ex) {
+            pw.println("Error: " + ex.toString());
+            return -1;
+        }
+        mInterface.setPowerSaveMode(mode == LOW_POWER_MODE_ON);
+        return 0;
+    }
+
+    @Override
+    public void onHelp() {
+        final PrintWriter pw = getOutPrintWriter();
+        pw.println("Power manager (power) commands:");
+        pw.println("  help");
+        pw.println("    Print this help text.");
+        pw.println("");
+        pw.println("  set-mode MODE");
+        pw.println("    sets the power mode of the device to MODE.");
+        pw.println("    1 turns low power mode on and 0 turns low power mode off.");
+        pw.println();
+        Intent.printIntentArgsHelp(pw , "");
+    }
+}