We need to work around the out-of-bound offset issue due to text-transform changing text length.

[115385:115385:0118/111930.788217:248257129262:FATAL:layout_text_fragment.cc(205)] Check failed: offset <= FragmentLength() (2 vs. 1)
#0 0x556ae6c7a49f base::debug::StackTrace::StackTrace()
#1 0x556ae6bd9cea logging::LogMessage::~LogMessage()
#2 0x556ae86fec63 blink::LayoutTextFragment::PositionForCaretOffset()
#3 0x556ae86f7162 blink::LayoutText::ResolvedTextLength()
#4 0x556ae86f74bd blink::LayoutText::HasNonCollapsedText()
#5 0x556ae80a86d8 blink::MostBackwardCaretPosition()
#6 0x556ae80a5253 blink::CanonicalPositionOf()
#7 0x556ae80a2911 blink::VisiblePositionTemplate<>::Create()
#8 0x556ae80a3942 blink::CreateVisiblePosition()
#9 0x556ae80a3b87 blink::VisibleSelectionTemplate<>::Creator::ComputeVisibleSelection()
#10 0x556ae80a4f8c blink::CreateVisibleSelection()
#11 0x556ae656ffb7 blink::VisibleSelectionTest_FirstLetterTextTransform_Test::TestBody()