Mass rewrite dtors to use "= default".

A simple search and replace with sed s/::~\(.*\) {}$/::~\1 = default;/
works surprisingly well.

Change-Id: Ie958265266e504006061e8f1b957046dfecd70dc
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/70251
Reviewed-by: Daniel Hosseinian <dhoss@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
diff --git a/xfa/fxfa/cxfa_ffrectangle.cpp b/xfa/fxfa/cxfa_ffrectangle.cpp
index ff5e576..1619f24 100644
--- a/xfa/fxfa/cxfa_ffrectangle.cpp
+++ b/xfa/fxfa/cxfa_ffrectangle.cpp
@@ -11,7 +11,7 @@
 
 CXFA_FFRectangle::CXFA_FFRectangle(CXFA_Node* pNode) : CXFA_FFWidget(pNode) {}
 
-CXFA_FFRectangle::~CXFA_FFRectangle() {}
+CXFA_FFRectangle::~CXFA_FFRectangle() = default;
 
 void CXFA_FFRectangle::RenderWidget(CXFA_Graphics* pGS,
                                     const CFX_Matrix& matrix,