Plumb selection bounds as a single unit

Source/web/tests/data/composited_selection_bounds_editable.html

Index: Source/web/tests/data/composited_selection_bounds_editable.html
diff --git a/Source/web/tests/data/composited_selection_bounds_editable.html b/Source/web/tests/data/composited_selection_bounds_editable.html
new file mode 100644
index 0000000000000000000000000000000000000000..ed54882b037516b28acf2d6a36a8e5f55a3a6a85
--- /dev/null
+++ b/Source/web/tests/data/composited_selection_bounds_editable.html
@@ -0,0 +1,24 @@
+<style>
+    @font-face {
+        font-family: ahem;
+        src: url(Ahem.ttf);
+    }
+    * {
+        font-family: ahem;
+        margin: 0;
+        padding: 0;
+    }
+</style>
+<textarea id="text">
+    The quick brown fox jumped over the lazy dog.
+</textarea>
+<script>
+    var textNode = document.getElementById("text");
+    textNode.focus();
+
+    var expectEditable = true;
+    var expectEmptyTextFormControl = false;
+    var yBottomEpsilon = 2;
+    window.expectedResult = [document, 1, 1, 1, 14, document, 1, 1, 1, 14, expectEditable, expectEmptyTextFormControl, yBottomEpsilon];
+</script>
+