cc: Remove unnecessary "default" cases from switch statements.

cc/animation/transform_operation.cc

Index: cc/animation/transform_operation.cc
diff --git a/cc/animation/transform_operation.cc b/cc/animation/transform_operation.cc
index b7bb0631c821fc458f2bfe9c55a70eb5979712ae..73892e5cec1a3a9aaab6aeb2bc177caba64f19b3 100644
--- a/cc/animation/transform_operation.cc
+++ b/cc/animation/transform_operation.cc
@@ -293,9 +293,13 @@ bool TransformOperation::BlendedBoundsForBox(const gfx::BoxF& box,
     case TransformOperation::TransformOperationIdentity:
       *bounds = box;
       return true;
-    default:
-      return false;
+    case TransformOperation::TransformOperationRotate:
+    case TransformOperation::TransformOperationSkew:
+    case TransformOperation::TransformOperationPerspective:
+    case TransformOperation::TransformOperationMatrix:
+      break;
   }
+  return false;
 }
 
 }  // namespace cc