Add component for feature engagement tracking.

components/feature_engagement_tracker/internal/android/java/src/org/chromium/components/feature_engagement_tracker/internal/FeatureEngagementTrackerImpl.java

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.components.feature_engagement_tracker.internal;
+
+import org.chromium.base.Callback;
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.base.annotations.JNINamespace;
+import org.chromium.components.feature_engagement_tracker.FeatureEngagementTracker;
+
+/**
+ * Java side of the JNI bridge between FeatureEngagementTrackerImpl in Java
+ * and C++. All method calls are delegated to the native C++ class.
+ */
+@JNINamespace("feature_engagement_tracker")
+public class FeatureEngagementTrackerImpl implements FeatureEngagementTracker {
+    /**
+     * The pointer to the FeatureEngagementTrackerImplAndroid JNI bridge.
+     */
+    private long mNativePtr;
+
+    @CalledByNative
+    private static FeatureEngagementTrackerImpl create(long nativePtr) {
+        return new FeatureEngagementTrackerImpl(nativePtr);
+    }
+
+    private FeatureEngagementTrackerImpl(long nativePtr) {
+        mNativePtr = nativePtr;
+    }
+
+    @Override
+    public void event(String feature, String precondition) {
+        assert mNativePtr != 0;
+        nativeEvent(mNativePtr, feature, precondition);
+    }
+
+    @Override
+    public void used(String feature) {
+        assert mNativePtr != 0;
+        nativeUsed(mNativePtr, feature);
+    }
+
+    @Override
+    public boolean trigger(String feature) {
+        assert mNativePtr != 0;
+        return nativeTrigger(mNativePtr, feature);
+    }
+
+    @Override
+    public void dismissed() {
+        assert mNativePtr != 0;
+        nativeDismissed(mNativePtr);
+    }
+
+    @Override
+    public void addOnInitializedCallback(Callback<Boolean> callback) {
+        assert mNativePtr != 0;
+        nativeAddOnInitializedCallback(mNativePtr, callback);
+    }
+
+    @CalledByNative
+    private void clearNativePtr() {
+        mNativePtr = 0;
+    }
+
+    @CalledByNative
+    private long getNativePtr() {
+        assert mNativePtr != 0;
+        return mNativePtr;
+    }
+
+    private native void nativeEvent(
+            long nativeFeatureEngagementTrackerImplAndroid, String feature, String precondition);
+    private native void nativeUsed(long nativeFeatureEngagementTrackerImplAndroid, String feature);
+    private native boolean nativeTrigger(
+            long nativeFeatureEngagementTrackerImplAndroid, String feature);
+    private native void nativeDismissed(long nativeFeatureEngagementTrackerImplAndroid);
+    private native void nativeAddOnInitializedCallback(
+            long nativeFeatureEngagementTrackerImplAndroid, Callback<Boolean> callback);
+}