[Editing][CodeHealth] remove default argument 'host' in EditingTestBase::setShadowContent

Source/core/editing/VisiblePositionTest.cpp

Index: Source/core/editing/VisiblePositionTest.cpp
diff --git a/Source/core/editing/VisiblePositionTest.cpp b/Source/core/editing/VisiblePositionTest.cpp
index 381ebfec59e235bbfb112c89508c68005af96f97..f8759045cb9e1075b3e6f224ef47c530e0b4d6b7 100644
--- a/Source/core/editing/VisiblePositionTest.cpp
+++ b/Source/core/editing/VisiblePositionTest.cpp
@@ -17,7 +17,7 @@ TEST_F(VisiblePositionTest, ShadowDistributedNodes)
     const char* bodyContent = "<p id='host'>00<b id='one'>11</b><b id='two'>22</b>33</p>";
     const char* shadowContent = "<a><span id='s4'>44</span><content select=#two></content><span id='s5'>55</span><content select=#one></content><span id='s6'>66</span></a>";
     setBodyContent(bodyContent);
-    RefPtrWillBeRawPtr<ShadowRoot> shadowRoot = setShadowContent(shadowContent);
+    RefPtrWillBeRawPtr<ShadowRoot> shadowRoot = setShadowContent(shadowContent, "host");
 
     RefPtrWillBeRawPtr<Element> body = document().body();
     RefPtrWillBeRawPtr<Element> one = body->querySelector("#one", ASSERT_NO_EXCEPTION);