[Sync] Add auto-generated ModelType in Java.

sync/android/java/src/org/chromium/sync/ModelTypeHelper.java

Index: sync/android/java/src/org/chromium/sync/ModelTypeHelper.java
diff --git a/sync/android/java/src/org/chromium/sync/ModelTypeHelper.java b/sync/android/java/src/org/chromium/sync/ModelTypeHelper.java
new file mode 100644
index 0000000000000000000000000000000000000000..7ae906de34262992031444f4fd87118b5aaa0061
--- /dev/null
+++ b/sync/android/java/src/org/chromium/sync/ModelTypeHelper.java
@@ -0,0 +1,96 @@
+// Copyright 2015 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.sync;
+
+import com.google.ipc.invalidation.external.client.types.ObjectId;
+import com.google.protos.ipc.invalidation.Types;
+
+import org.chromium.base.FieldTrialList;
+import org.chromium.base.JNINamespace;
+import org.chromium.base.VisibleForTesting;
+import org.chromium.base.library_loader.LibraryLoader;
+
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * Helper methods for dealing with ModelTypes.
+ */
+@JNINamespace("syncer")
+public class ModelTypeHelper {
+    private static final String TAG = "ModelTypeHelper";
+
+    private static final int[] NON_INVALIDATION_TYPES_ARRAY = new int[] {
+        ModelType.PROXY_TABS
+    };
+
+    private static Set<String> sNonInvalidationTypes = null;
+    private static Set<String> sTypesDisabledForExperiment = null;
+
+    private static void initNonInvalidationTypes() {
+        sNonInvalidationTypes = new HashSet<String>();
+        for (int i = 0; i < NON_INVALIDATION_TYPES_ARRAY.length; i++) {
+            sNonInvalidationTypes.add(toString(NON_INVALIDATION_TYPES_ARRAY[i]));
+        }
+        sTypesDisabledForExperiment = new HashSet<String>();
+        sTypesDisabledForExperiment.add(toString(ModelType.SESSIONS));
+        sTypesDisabledForExperiment.add(toString(ModelType.FAVICON_TRACKING));
+        sTypesDisabledForExperiment.add(toString(ModelType.FAVICON_IMAGES));
+    }
+
+    private static boolean isInvalidationType(String modelType) {
+        if (sNonInvalidationTypes == null) {
+            initNonInvalidationTypes();
+        }
+        if (sTypesDisabledForExperiment.contains(modelType) && LibraryLoader.isInitialized()) {
+            return !FieldTrialList.findFullName("AndroidSessionNotifications").equals("Disabled");
+        }
+        return !sNonInvalidationTypes.contains(modelType);
+    }
+
+    private static ObjectId toObjectId(String modelType) {
+        return ObjectId.newInstance(Types.ObjectSource.CHROME_SYNC, modelType.getBytes());
+    }
+
+    @VisibleForTesting
+    public static ObjectId toObjectId(int modelType) {
+        return toObjectId(toString(modelType));
+    }
+
+    /**
+     * Converts a model type to its string representation using JNI.
+     * This is the value that is stored in the invalidation preferences.
+     *
+     * @param modelType the model type to convert to a string.
+     * @return the string representation of the model type constant.
+     */
+    public static String toString(Integer modelType) {
+        // Because PROXY_TABS isn't an invalidation type, it doesn't have a string from native,
+        // but for backwards compatibility we need to keep its pref value the same as the old
+        // ModelType enum name value.
+        if (modelType == ModelType.PROXY_TABS) {
+            return "PROXY_TABS";
+        }
+        return nativeModelTypeToString(modelType);
+    }
+
+    /**
+     * Converts a set of {@link String} model types to a set of {@link ObjectId}.
+     *
+     * This strips out any {@link ModelType} that is not an invalidation type.
+     */
+    public static Set<ObjectId> modelTypeStringsToObjectIds(Collection<String> modelTypes) {
+        Set<ObjectId> objectIds = new HashSet<ObjectId>();
+        for (String modelType : modelTypes) {
+            if (isInvalidationType(modelType)) {
+                objectIds.add(toObjectId(modelType));
+            }
+        }
+        return objectIds;
+    }
+
+    private static native String nativeModelTypeToString(int modelType);
+}