Get Vibrator from Context instead of using private API.

Bug: 6334179
Change-Id: I55ee28578ba8ac22168c3578e4888b2235442884
diff --git a/src/com/android/inputmethod/pinyin/SoftKeyboardView.java b/src/com/android/inputmethod/pinyin/SoftKeyboardView.java
index 5543f33..bd74701 100644
--- a/src/com/android/inputmethod/pinyin/SoftKeyboardView.java
+++ b/src/com/android/inputmethod/pinyin/SoftKeyboardView.java
@@ -380,7 +380,7 @@
             return;
         }
         if (mVibrator == null) {
-            mVibrator = new Vibrator();
+            mVibrator = (Vibrator)getContext().getSystemService(Context.VIBRATOR_SERVICE);
         }
         mVibrator.vibrate(mVibratePattern, -1);
     }