inflate transport popup opportunistically

Closes #3763
// FREEBIE

src/org/thoughtcrime/securesms/components/SendButton.java

@@ -9,6 +9,7 @@ import org.thoughtcrime.securesms.TransportOption;
 import org.thoughtcrime.securesms.TransportOptions;
 import org.thoughtcrime.securesms.TransportOptions.OnTransportChangedListener;
 import org.thoughtcrime.securesms.TransportOptionsPopup;
+import org.whispersystems.libaxolotl.util.guava.Optional;
 
 public class SendButton extends ImageButton
     implements TransportOptions.OnTransportChangedListener,
@@ -17,27 +18,25 @@ public class SendButton extends ImageButton
 {
 
   private final TransportOptions transportOptions;
-  private final TransportOptionsPopup transportOptionsPopup;
+
+  private Optional<TransportOptionsPopup> transportOptionsPopup = Optional.absent();
 
   @SuppressWarnings("unused")
   public SendButton(Context context) {
     super(context);
     this.transportOptions = initializeTransportOptions(false);
-    this.transportOptionsPopup = initializeTransportOptionsPopup();
   }
 
   @SuppressWarnings("unused")
   public SendButton(Context context, AttributeSet attrs) {
     super(context, attrs);
     this.transportOptions = initializeTransportOptions(false);
-    this.transportOptionsPopup = initializeTransportOptionsPopup();
   }
 
   @SuppressWarnings("unused")
   public SendButton(Context context, AttributeSet attrs, int defStyle) {
     super(context, attrs, defStyle);
     this.transportOptions = initializeTransportOptions(false);
-    this.transportOptionsPopup = initializeTransportOptionsPopup();
   }
 
   private TransportOptions initializeTransportOptions(boolean media) {
@@ -49,8 +48,11 @@ public class SendButton extends ImageButton
     return transportOptions;
   }
 
-  private TransportOptionsPopup initializeTransportOptionsPopup() {
-    return new TransportOptionsPopup(getContext(), this, this);
+  private TransportOptionsPopup getTransportOptionsPopup() {
+    if (!transportOptionsPopup.isPresent()) {
+      transportOptionsPopup = Optional.of(new TransportOptionsPopup(getContext(), this, this));
+    }
+    return transportOptionsPopup.get();
   }
 
   public boolean isManualSelection() {
@@ -80,7 +82,7 @@ public class SendButton extends ImageButton
   @Override
   public void onSelected(TransportOption option) {
     transportOptions.setSelectedTransport(option.getType());
-    transportOptionsPopup.dismiss();
+    getTransportOptionsPopup().dismiss();
   }
 
   @Override
@@ -92,7 +94,7 @@ public class SendButton extends ImageButton
   @Override
   public boolean onLongClick(View v) {
     if (transportOptions.getEnabledTransports().size() > 1) {
-      transportOptionsPopup.display(transportOptions.getEnabledTransports());
+      getTransportOptionsPopup().display(transportOptions.getEnabledTransports());
       return true;
     }