Include opacity in FadeTransition logging (#15073)

packages/flutter/lib/src/widgets/animated_cross_fade.dart

diff --git a/packages/flutter/lib/src/widgets/animated_cross_fade.dart b/packages/flutter/lib/src/widgets/animated_cross_fade.dart
index 58bb65d..5394858 100644
--- a/packages/flutter/lib/src/widgets/animated_cross_fade.dart
+++ b/packages/flutter/lib/src/widgets/animated_cross_fade.dart
@@ -247,13 +247,13 @@
   Animation<double> _initAnimation(Curve curve, bool inverted) {
     Animation<double> animation = new CurvedAnimation(
       parent: _controller,
-      curve: curve
+      curve: curve,
     );
 
     if (inverted) {
       animation = new Tween<double>(
-          begin: 1.0,
-          end: 0.0
+        begin: 1.0,
+        end: 0.0,
       ).animate(animation);
     }
 

packages/flutter/lib/src/widgets/transitions.dart

diff --git a/packages/flutter/lib/src/widgets/transitions.dart b/packages/flutter/lib/src/widgets/transitions.dart
index 9d2d409..c41f22a 100644
--- a/packages/flutter/lib/src/widgets/transitions.dart
+++ b/packages/flutter/lib/src/widgets/transitions.dart
@@ -332,6 +332,12 @@
     renderObject
       ..opacity = opacity;
   }
+
+  @override
+  void debugFillProperties(DiagnosticPropertiesBuilder description) {
+    super.debugFillProperties(description);
+    description.add(new DiagnosticsProperty<Animation<double>>('opacity', opacity));
+  }
 }
 
 /// An interpolation between two relative rects.