Update the timestamp we send in touch events to be the more accurate timestamp we use

Summary: Use the more accurate timestamp that we have computed for the touch event rather than the event timestamp that Android provides.

Reviewed By: andreicoman11

Differential Revision: D3292705

fbshipit-source-id: dad082ab74406d391481d16cdac19629751aa1eb

ReactAndroid/src/main/java/com/facebook/react/uimanager/events/TouchesHelper.java

@@ -62,7 +62,7 @@ import com.facebook.react.uimanager.PixelUtil;
       touch.putDouble(LOCATION_X_KEY, PixelUtil.toDIPFromPixel(locationX));
       touch.putDouble(LOCATION_Y_KEY, PixelUtil.toDIPFromPixel(locationY));
       touch.putInt(TARGET_KEY, reactTarget);
-      touch.putDouble(TIMESTAMP_KEY, motionEvent.getEventTime());
+      touch.putDouble(TIMESTAMP_KEY, event.getTimestampMs());
       touch.putDouble(POINTER_IDENTIFIER_KEY, motionEvent.getPointerId(index));
       touches.pushMap(touch);
     }

ReactAndroid/src/test/java/com/facebook/react/RootViewTest.java

@@ -22,6 +22,7 @@ import com.facebook.react.bridge.ReactTestHelper;
 import com.facebook.react.bridge.JavaOnlyArray;
 import com.facebook.react.bridge.JavaOnlyMap;
 import com.facebook.react.bridge.WritableArray;
+import com.facebook.react.common.SystemClock;
 import com.facebook.react.uimanager.UIManagerModule;
 import com.facebook.react.uimanager.DisplayMetricsHolder;
 import com.facebook.react.uimanager.events.Event;
@@ -51,7 +52,7 @@ import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoMoreInteractions;
 import static org.mockito.Mockito.when;
 
-@PrepareForTest(Arguments.class)
+@PrepareForTest({Arguments.class, SystemClock.class})
 @RunWith(RobolectricTestRunner.class)
 @PowerMockIgnore({"org.mockito.*", "org.robolectric.*", "android.*"})
 public class RootViewTest {
@@ -64,6 +65,7 @@ public class RootViewTest {
 
   @Before
   public void setUp() {
+    final long ts = SystemClock.nanoTime();
     PowerMockito.mockStatic(Arguments.class);
     PowerMockito.when(Arguments.createArray()).thenAnswer(new Answer<Object>() {
       @Override
@@ -77,6 +79,13 @@ public class RootViewTest {
         return new JavaOnlyMap();
       }
     });
+    PowerMockito.mockStatic(SystemClock.class);
+    PowerMockito.when(SystemClock.nanoTime()).thenAnswer(new Answer<Object>() {
+      @Override
+      public Object answer(InvocationOnMock invocation) throws Throwable {
+        return ts;
+      }
+    });
 
     mCatalystInstanceMock = ReactTestHelper.createMockCatalystInstance();
     mReactContext = new ReactApplicationContext(RuntimeEnvironment.application);
@@ -107,7 +116,7 @@ public class RootViewTest {
     rootView.startReactApplication(instanceManager, "");
     rootView.simulateAttachForTesting();
 
-    long ts = new Date().getTime();
+    long ts = SystemClock.nanoTime();
 
     // Test ACTION_DOWN event
     rootView.onTouchEvent(