Use FrameSelection::selectedText where possible.

third_party/WebKit/Source/core/html/HTMLTextFormControlElement.cpp

Index: third_party/WebKit/Source/core/html/HTMLTextFormControlElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLTextFormControlElement.cpp b/third_party/WebKit/Source/core/html/HTMLTextFormControlElement.cpp
index b3421b15e87f3c948e148727b9f18a554e1b5353..3384b7b6c5d5b56b44e07e2d8cd59a782759e004 100644
--- a/third_party/WebKit/Source/core/html/HTMLTextFormControlElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLTextFormControlElement.cpp
@@ -189,6 +189,7 @@ void HTMLTextFormControlElement::setSelectionDirection(const String& direction)
 
 void HTMLTextFormControlElement::select(NeedToDispatchSelectEvent eventBehaviour)
 {
+    // We have to update layout here to use isFocusable().
     document().updateLayoutIgnorePendingStylesheets();
     setSelectionRange(0, std::numeric_limits<int>::max(), SelectionHasNoDirection, eventBehaviour, isFocusable() ? ChangeSelectionAndFocus : NotChangeSelection);
 }
@@ -354,6 +355,10 @@ void HTMLTextFormControlElement::setSelectionRange(int start, int end, TextField
     if (openShadowRoot() || !isTextFormControl() || !inDocument())
         return;
 
+    // We need to update layout here so that we have proper types for both dom tree and composed tree selection.
+    // See https://codereview.chromium.org/1377963004/
+    document().updateLayoutIgnorePendingStylesheets();
+
     const int editorValueLength = static_cast<int>(innerEditorValue().length());
     ASSERT(editorValueLength >= 0);
     end = std::max(std::min(end, editorValueLength), 0);