Revert "Instantiate a ModifiedFocusNode2 corresponding to a Modifier.focus() modifier"

This reverts commit 79b361fcb1a863005e834f70a88cae274f6ca3ce.

Reason for revert: This CL broke the build.

Change-Id: I3dcf0b427b25de791d9fdf32cba01cdad4ce54cf
diff --git a/ui/ui-core/src/commonMain/kotlin/androidx/ui/core/LayoutNode.kt b/ui/ui-core/src/commonMain/kotlin/androidx/ui/core/LayoutNode.kt
index 634c373..62e6b9c 100644
--- a/ui/ui-core/src/commonMain/kotlin/androidx/ui/core/LayoutNode.kt
+++ b/ui/ui-core/src/commonMain/kotlin/androidx/ui/core/LayoutNode.kt
@@ -22,10 +22,8 @@
 import androidx.ui.core.LayoutNode.LayoutState.NeedsRemeasure
 import androidx.ui.core.LayoutNode.LayoutState.Ready
 import androidx.ui.core.focus.FocusModifier
-import androidx.ui.core.focus.FocusModifier2
 import androidx.ui.core.focus.FocusModifierImpl
 import androidx.ui.core.focus.ModifiedFocusNode
-import androidx.ui.core.focus.ModifiedFocusNode2
 import androidx.ui.core.keyinput.KeyInputModifier
 import androidx.ui.core.keyinput.ModifiedKeyInputNode
 import androidx.ui.core.pointerinput.PointerInputFilter
@@ -556,9 +554,6 @@
                         wrapper = ModifiedFocusNode(wrapper, mod).also { mod.focusNode = it }
                             .assignChained(toWrap)
                     }
-                    if (mod is FocusModifier2) {
-                        wrapper = ModifiedFocusNode2(wrapper, mod).assignChained(toWrap)
-                    }
                     if (mod is KeyInputModifier) {
                         wrapper = ModifiedKeyInputNode(wrapper, mod).also { mod.keyInputNode = it }
                             .assignChained(toWrap)
@@ -1046,7 +1041,7 @@
                     constraints: Constraints,
                     layoutDirection: LayoutDirection
                 ) = error("Undefined measure and it is required")
-            }
+        }
     }
 
     /**