Return to archive on back button press in archived convo

When the back/up/home button in the action bar is pressed in an
archived conversation, return to the archive instead of the inbox.

Closes #4770
// FREEBIE

src/org/thoughtcrime/securesms/ConversationActivity.java

@@ -163,6 +163,7 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
 
   public static final String RECIPIENTS_EXTRA        = "recipients";
   public static final String THREAD_ID_EXTRA         = "thread_id";
+  public static final String IS_ARCHIVED_EXTRA       = "is_archived";
   public static final String TEXT_EXTRA              = "draft_text";
   public static final String DISTRIBUTION_TYPE_EXTRA = "distribution_type";
 
@@ -199,6 +200,7 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
   private Recipients recipients;
   private long       threadId;
   private int        distributionType;
+  private boolean    archived;
   private boolean    isSecureText;
   private boolean    isSecureVoice;
   private boolean    isMmsEnabled = true;
@@ -426,7 +428,7 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
   //////// Event Handlers
 
   private void handleReturnToConversationList() {
-    Intent intent = new Intent(this, ConversationListActivity.class);
+    Intent intent = new Intent(this, (archived ? ConversationListArchiveActivity.class : ConversationListActivity.class));
     intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
     startActivity(intent);
     finish();
@@ -917,6 +919,7 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
     
     recipients       = RecipientFactory.getRecipientsForIds(this, getIntent().getLongArrayExtra(RECIPIENTS_EXTRA), true);
     threadId         = getIntent().getLongExtra(THREAD_ID_EXTRA, -1);
+    archived         = getIntent().getBooleanExtra(IS_ARCHIVED_EXTRA, false);
     distributionType = getIntent().getIntExtra(DISTRIBUTION_TYPE_EXTRA, ThreadDatabase.DistributionTypes.DEFAULT);
 
     if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {

src/org/thoughtcrime/securesms/ConversationListArchiveActivity.java

@@ -57,6 +57,7 @@ public class ConversationListArchiveActivity extends PassphraseRequiredActionBar
     Intent intent = new Intent(this, ConversationActivity.class);
     intent.putExtra(ConversationActivity.RECIPIENTS_EXTRA, recipients.getIds());
     intent.putExtra(ConversationActivity.THREAD_ID_EXTRA, threadId);
+    intent.putExtra(ConversationActivity.IS_ARCHIVED_EXTRA, true);
     intent.putExtra(ConversationActivity.DISTRIBUTION_TYPE_EXTRA, distributionType);
 
     startActivity(intent);