Fix the transition of the up-button.

We've applied a new transition from Search to Settings, where if users
click on the up-button, the transition will not be applied. Hence, this
CL makes the up-button behave the same as the back key to address this.

- Also remove the transition target as it is not necessary.

Fixes: 177968777
Test: 1. Search "Gesture"
2. Click on "Gesture"
3. Tap the up-button and see the applied transition

Change-Id: I046424f244426750d98046703c05ae0a1d567c67

src/com/android/settings/SettingsActivity.java

@@ -238,12 +238,10 @@ public class SettingsActivity extends SettingsBaseActivity
             getWindow().requestFeature(Window.FEATURE_ACTIVITY_TRANSITIONS);
             final MaterialSharedAxis enterTransition = new MaterialSharedAxis(
                     MaterialSharedAxis.X, /* forward */true);
-            enterTransition.addTarget(R.id.content_parent);
             getWindow().setEnterTransition(enterTransition);
 
             final MaterialSharedAxis returnTransition = new MaterialSharedAxis(
                     MaterialSharedAxis.X, /* forward */false);
-            returnTransition.addTarget(R.id.content_parent);
             getWindow().setReturnTransition(returnTransition);
         }
 

src/com/android/settings/core/SettingsBaseActivity.java

@@ -32,11 +32,13 @@ import android.util.ArraySet;
 import android.util.FeatureFlagUtils;
 import android.util.Log;
 import android.view.LayoutInflater;
+import android.view.MenuItem;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.Window;
 import android.widget.Toolbar;
 
+import androidx.annotation.NonNull;
 import androidx.fragment.app.FragmentActivity;
 
 import com.android.settings.R;
@@ -167,6 +169,17 @@ public class SettingsBaseActivity extends FragmentActivity {
         ((ViewGroup) findViewById(R.id.content_frame)).addView(view, params);
     }
 
+    @Override
+    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
+        final int id = item.getItemId();
+        if (id == android.R.id.home) {
+            // Make the up button behave the same as the back button.
+            onBackPressed();
+            return true;
+        }
+        return super.onOptionsItemSelected(item);
+    }
+
     @Override
     public void setTitle(CharSequence title) {
         if (mCollapsingToolbarLayout != null) {