Support for stopping animations that run on UI thread.

Summary:This change extends animated native module API with `stopAnimation` method that is responsible for interrupting actively running animation as a reslut of a JS call. In order for the `stopAnimation` to understand `animationId` argument I also had to add `animationId` to `startAnimation` method. As JS thread runs in parallel to the thread which executes the animation there is a chance that JS may call `stopAnimation` after the animation has finished. Because of that we are not doing any checks on the `animationId` parameter passed to `stopAnimation` in native and if the animation does not exists in the registry we ignore that call.

**Test Plan**
Run JS tests: `npm test Libraries/Animated/src/__tests__/AnimatedNative-test.js`
Run java tests: `buck test ReactAndroid/src/test/java/com/facebook/react/animated`
Closes https://github.com/facebook/react-native/pull/7058

Differential Revision: D3211906

fb-gh-sync-id: 3761509651de36a550b00d33e2a631c379d3900f
fbshipit-source-id: 3761509651de36a550b00d33e2a631c379d3900f

ReactAndroid/src/main/java/com/facebook/react/animated/AnimationDriver.java

@@ -17,9 +17,10 @@ import com.facebook.react.bridge.Callback;
  */
 /*package*/ abstract class AnimationDriver {
 
-  boolean mHasFinished = false;
-  ValueAnimatedNode mAnimatedValue;
-  Callback mEndCallback;
+  /*package*/ boolean mHasFinished = false;
+  /*package*/ ValueAnimatedNode mAnimatedValue;
+  /*package*/ Callback mEndCallback;
+  /*package*/ int mId;
 
   /**
    * This method gets called in the main animation loop with a frame time passed down from the

ReactAndroid/src/main/java/com/facebook/react/animated/NativeAnimatedModule.java

@@ -212,6 +212,7 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule implements
 
   @ReactMethod
   public void startAnimatingNode(
+      final int animationId,
       final int animatedNodeTag,
       final ReadableMap animationConfig,
       final Callback endCallback) {
@@ -219,6 +220,7 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule implements
       @Override
       public void execute(NativeAnimatedNodesManager animatedNodesManager) {
         animatedNodesManager.startAnimatingNode(
+          animationId,
           animatedNodeTag,
           animationConfig,
           endCallback);
@@ -226,6 +228,16 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule implements
     });
   }
 
+  @ReactMethod
+  public void stopAnimation(final int animationId) {
+    mOperations.add(new UIThreadOperation() {
+      @Override
+      public void execute(NativeAnimatedNodesManager animatedNodesManager) {
+        animatedNodesManager.stopAnimation(animationId);
+      }
+    });
+  }
+
   @ReactMethod
   public void connectAnimatedNodes(final int parentNodeTag, final int childNodeTag) {
     mOperations.add(new UIThreadOperation() {

ReactAndroid/src/main/java/com/facebook/react/animated/NativeAnimatedNodesManager.java

@@ -98,6 +98,7 @@ import javax.annotation.Nullable;
   }
 
   public void startAnimatingNode(
+    int animationId,
     int animatedNodeTag,
     ReadableMap animationConfig,
     Callback endCallback) {
@@ -117,11 +118,34 @@ import javax.annotation.Nullable;
     } else {
       throw new JSApplicationIllegalArgumentException("Unsupported animation type: " + type);
     }
+    animation.mId = animationId;
     animation.mEndCallback = endCallback;
     animation.mAnimatedValue = (ValueAnimatedNode) node;
     mActiveAnimations.add(animation);
   }
 
+  public void stopAnimation(int animationId) {
+    // in most of the cases there should never be more than a few active animations running at the
+    // same time. Therefore it does not make much sense to create an animationId -> animation
+    // object map that would require additional memory just to support the use-case of stopping
+    // an animation
+    for (int i = 0; i < mActiveAnimations.size(); i++) {
+      AnimationDriver animation = mActiveAnimations.get(i);
+      if (animation.mId == animationId) {
+        // Invoke animation end callback with {finished: false}
+        WritableMap endCallbackResponse = Arguments.createMap();
+        endCallbackResponse.putBoolean("finished", false);
+        animation.mEndCallback.invoke(endCallbackResponse);
+        mActiveAnimations.remove(i);
+        return;
+      }
+    }
+    // Do not throw an error in the case animation could not be found. We only keep "active"
+    // animations in the registry and there is a chance that Animated.js will enqueue a
+    // stopAnimation call after the animation has ended or the call will reach native thread only
+    // when the animation is already over.
+  }
+
   public void connectAnimatedNodes(int parentNodeTag, int childNodeTag) {
     AnimatedNode parentNode = mAnimatedNodes.get(parentNodeTag);
     if (parentNode == null) {