Added ability to share contacts.

The "contact" option in the attachments tray now brings you through an
optimized contact sharing flow, allowing you to select specific fields
to share. The contact is then presented as a special message type,
allowing you to interact with the card to add the contact to your system
contacts, invite them to signal, initiate a signal message, etc.

src/org/thoughtcrime/securesms/util/CommunicationActions.java

@@ -0,0 +1,79 @@
+package org.thoughtcrime.securesms.util;
+
+import android.Manifest;
+import android.app.Activity;
+import android.content.Context;
+import android.content.Intent;
+import android.net.Uri;
+import android.os.AsyncTask;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.text.TextUtils;
+
+import org.thoughtcrime.securesms.ConversationActivity;
+import org.thoughtcrime.securesms.R;
+import org.thoughtcrime.securesms.WebRtcCallActivity;
+import org.thoughtcrime.securesms.contactshare.Contact;
+import org.thoughtcrime.securesms.database.Address;
+import org.thoughtcrime.securesms.database.DatabaseFactory;
+import org.thoughtcrime.securesms.permissions.Permissions;
+import org.thoughtcrime.securesms.recipients.Recipient;
+import org.thoughtcrime.securesms.service.WebRtcCallService;
+
+public class CommunicationActions {
+
+  public static void startVoiceCall(@NonNull Activity activity, @NonNull Recipient recipient) {
+    Permissions.with(activity)
+        .request(Manifest.permission.RECORD_AUDIO, Manifest.permission.CAMERA)
+        .ifNecessary()
+        .withRationaleDialog(activity.getString(R.string.ConversationActivity_to_call_s_signal_needs_access_to_your_microphone_and_camera, recipient.toShortString()),
+                             R.drawable.ic_mic_white_48dp,
+                             R.drawable.ic_videocam_white_48dp)
+        .withPermanentDenialDialog(activity.getString(R.string.ConversationActivity_signal_needs_the_microphone_and_camera_permissions_in_order_to_call_s, recipient.toShortString()))
+        .onAllGranted(() -> {
+          Intent intent = new Intent(activity, WebRtcCallService.class);
+          intent.setAction(WebRtcCallService.ACTION_OUTGOING_CALL);
+          intent.putExtra(WebRtcCallService.EXTRA_REMOTE_ADDRESS, recipient.getAddress());
+          activity.startService(intent);
+
+          Intent activityIntent = new Intent(activity, WebRtcCallActivity.class);
+          activityIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+          activity.startActivity(activityIntent);
+        })
+        .execute();
+  }
+
+  public static void startConversation(@NonNull  Context   context,
+                                       @NonNull  Recipient recipient,
+                                       @Nullable String    text)
+  {
+    new AsyncTask<Void, Void, Long>() {
+      @Override
+      protected Long doInBackground(Void... voids) {
+        return DatabaseFactory.getThreadDatabase(context).getThreadIdFor(recipient);
+      }
+
+      @Override
+      protected void onPostExecute(Long threadId) {
+        Intent intent = new Intent(context, ConversationActivity.class);
+        intent.putExtra(ConversationActivity.ADDRESS_EXTRA, recipient.getAddress());
+        intent.putExtra(ConversationActivity.THREAD_ID_EXTRA, threadId);
+        intent.putExtra(ConversationActivity.TIMING_EXTRA, System.currentTimeMillis());
+
+        if (!TextUtils.isEmpty(text)) {
+          intent.putExtra(ConversationActivity.TEXT_EXTRA, text);
+        }
+
+        context.startActivity(intent);
+      }
+    }.execute();
+  }
+
+  public static void composeSmsThroughDefaultApp(@NonNull Context context, @NonNull Address address, @Nullable String text) {
+    Intent intent = new Intent(Intent.ACTION_SENDTO, Uri.parse("smsto:" + address.serialize()));
+    if (text != null) {
+      intent.putExtra("sms_body", text);
+    }
+    context.startActivity(intent);
+  }
+}

src/org/thoughtcrime/securesms/util/JsonUtils.java

@@ -2,6 +2,7 @@ package org.thoughtcrime.securesms.util;
 
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
 
 import org.json.JSONException;
 import org.json.JSONObject;
@@ -17,6 +18,8 @@ public class JsonUtils {
 
   static {
     objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
+    objectMapper.enable(SerializationFeature.WRITE_ENUMS_USING_TO_STRING);
+    objectMapper.enable(DeserializationFeature.READ_ENUMS_USING_TO_STRING);
   }
 
   public static <T> T fromJson(byte[] serialized, Class<T> clazz) throws IOException {

src/org/thoughtcrime/securesms/util/MediaUtil.java

@@ -3,13 +3,11 @@ package org.thoughtcrime.securesms.util;
 import android.content.ContentResolver;
 import android.content.Context;
 import android.graphics.Bitmap;
-import android.graphics.drawable.BitmapDrawable;
 import android.net.Uri;
 import android.provider.MediaStore;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.support.annotation.WorkerThread;
-import android.support.media.ExifInterface;
 import android.text.TextUtils;
 import android.util.Log;
 import android.util.Pair;

src/org/thoughtcrime/securesms/util/SingleLiveEvent.java

@@ -0,0 +1,72 @@
+/*
+ *  Copyright 2017 Google Inc.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+package org.thoughtcrime.securesms.util;
+
+import android.arch.lifecycle.LifecycleOwner;
+import android.arch.lifecycle.MutableLiveData;
+import android.arch.lifecycle.Observer;
+import android.support.annotation.MainThread;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.util.Log;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
+/**
+ * A lifecycle-aware observable that sends only new updates after subscription, used for events like
+ * navigation and Snackbar messages.
+ * <p>
+ * This avoids a common problem with events: on configuration change (like rotation) an update
+ * can be emitted if the observer is active. This LiveData only calls the observable if there's an
+ * explicit call to setValue() or call().
+ * <p>
+ * Note that only one observer is going to be notified of changes.
+ */
+public class SingleLiveEvent<T> extends MutableLiveData<T> {
+
+  private static final String TAG = SingleLiveEvent.class.getSimpleName();
+
+  private final AtomicBoolean mPending = new AtomicBoolean(false);
+
+  @MainThread
+  public void observe(@NonNull LifecycleOwner owner, @NonNull final Observer<T> observer) {
+    if (hasActiveObservers()) {
+      Log.w(TAG, "Multiple observers registered but only one will be notified of changes.");
+    }
+
+    // Observe the internal MutableLiveData
+    super.observe(owner, t -> {
+      if (mPending.compareAndSet(true, false)) {
+        observer.onChanged(t);
+      }
+    });
+  }
+
+  @MainThread
+  public void setValue(@Nullable T t) {
+    mPending.set(true);
+    super.setValue(t);
+  }
+
+  /**
+   * Used for cases where T is Void, to make calls cleaner.
+   */
+  @MainThread
+  public void call() {
+    setValue(null);
+  }
+}