Get android.os tests running against real APIs.

Combination of moving to existing public API, tagging things as
@TestApi, and bringing utility methods into tests.

Bug: 13282254
Test: atest cts/tests/tests/os/
Change-Id: Ifd24c0d048d200e8595e194890cc1dc53ddc2b3e
diff --git a/core/java/android/os/VibrationEffect.java b/core/java/android/os/VibrationEffect.java
index 91c69fb..01d85c6 100644
--- a/core/java/android/os/VibrationEffect.java
+++ b/core/java/android/os/VibrationEffect.java
@@ -54,6 +54,7 @@
      * @see #get(int)
      * @hide
      */
+    @TestApi
     public static final int EFFECT_CLICK = Effect.CLICK;
 
     /**
@@ -62,6 +63,7 @@
      * @see #get(int)
      * @hide
      */
+    @TestApi
     public static final int EFFECT_DOUBLE_CLICK = Effect.DOUBLE_CLICK;
 
     /**
@@ -69,6 +71,7 @@
      * @see #get(int)
      * @hide
      */
+    @TestApi
     public static final int EFFECT_TICK = Effect.TICK;
 
     /**
@@ -76,6 +79,7 @@
      * @see #get(int)
      * @hide
      */
+    @TestApi
     public static final int EFFECT_THUD = Effect.THUD;
 
     /**
@@ -83,6 +87,7 @@
      * @see #get(int)
      * @hide
      */
+    @TestApi
     public static final int EFFECT_POP = Effect.POP;
 
     /**
@@ -90,8 +95,20 @@
      * @see #get(int)
      * @hide
      */
+    @TestApi
     public static final int EFFECT_HEAVY_CLICK = Effect.HEAVY_CLICK;
 
+    /** {@hide} */
+    @TestApi
+    public static final int EFFECT_STRENGTH_LIGHT = EffectStrength.LIGHT;
+
+    /** {@hide} */
+    @TestApi
+    public static final int EFFECT_STRENGTH_MEDIUM = EffectStrength.MEDIUM;
+
+    /** {@hide} */
+    @TestApi
+    public static final int EFFECT_STRENGTH_STRONG = EffectStrength.STRONG;
 
     /**
      * Ringtone patterns. They may correspond with the device's ringtone audio, or may just be a
@@ -307,6 +324,7 @@
      *
      * @hide
      */
+    @TestApi
     public abstract long getDuration();
 
     /**