Refactor CaptionAppearanceFragment to improve maintainability (3/n)

Root cause: There is a bunch of different logic of preferences in CaptionAppearanceFragment. It’s hard to implement new features and hard to maintain and hard to be testable.
Solution: Move out color and edge preference logic of CaptionAppearanceFragment into controllers to reduce the complexity of the relationship between preference and fragment.

Bug: 197695932
Test: make RunSettingsRoboTests ROBOTEST_FILTER=com.android.settings.accessibility
Change-Id: I8ed80b445a0d376a7e9dda87feda82420a78a9da

tests/robotests/src/com/android/settings/accessibility/CaptionHelperTest.java

@@ -28,6 +28,7 @@ import android.content.Context;
 import android.provider.Settings;
 import android.view.View;
 import android.view.accessibility.CaptioningManager;
+import android.view.accessibility.CaptioningManager.CaptionStyle;
 
 import androidx.test.core.app.ApplicationProvider;
 
@@ -129,4 +130,44 @@ public class CaptionHelperTest {
                 Settings.Secure.ACCESSIBILITY_CAPTIONING_ENABLED, OFF) == ON;
         assertThat(isCaptionEnabled).isFalse();
     }
+
+    @Test
+    public void setBackgroundColor_shouldReturnSpecificColor() {
+        mCaptionHelper.setBackgroundColor(0xFFFF0000);
+
+        final int backgroundColor = mCaptionHelper.getBackgroundColor();
+        assertThat(backgroundColor).isEqualTo(0xFFFF0000);
+    }
+
+    @Test
+    public void setForegroundColor_shouldReturnSpecificColor() {
+        mCaptionHelper.setForegroundColor(0xFFFF0000);
+
+        final int foregroundColor = mCaptionHelper.getForegroundColor();
+        assertThat(foregroundColor).isEqualTo(0xFFFF0000);
+    }
+
+    @Test
+    public void setWindowColor_shouldReturnSpecificColor() {
+        mCaptionHelper.setWindowColor(0xFFFF0000);
+
+        final int windowColor = mCaptionHelper.getWindowColor();
+        assertThat(windowColor).isEqualTo(0xFFFF0000);
+    }
+
+    @Test
+    public void setEdgeColor_shouldReturnSpecificColor() {
+        mCaptionHelper.setEdgeColor(0xFFFF0000);
+
+        final int edgeColor = mCaptionHelper.getEdgeColor();
+        assertThat(edgeColor).isEqualTo(0xFFFF0000);
+    }
+
+    @Test
+    public void setEdgeType_shouldReturnSpecificType() {
+        mCaptionHelper.setEdgeType(CaptionStyle.EDGE_TYPE_OUTLINE);
+
+        final int edgeType = mCaptionHelper.getEdgeType();
+        assertThat(edgeType).isEqualTo(CaptionStyle.EDGE_TYPE_OUTLINE);
+    }
 }