Make code compile with clang_use_chrome_plugin (part V)chromium/2770

This change mainly contains files in xfa/fxfa directory.
This is part of the efforts to make PDFium code compilable
by Clang chromium style plugins.

The changes are mainly the following:
-- move inline constructor/destructor of complex class/struct out-of-line;
-- add constructor/destructor of complex class/struct if not
 explicitly defined;
-- add explicit out-of-line copy constructor when needed;
-- move inline virtual functions out-of-line;
-- Properly mark virtual functions with 'override';
-- some minor cleanups;

BUG=pdfium:469

Review-Url: https://codereview.chromium.org/2071683002

1 files changed, 4 insertions, 0 deletions

diff --git a/xfa/fxfa/app/xfa_ffpageview.cpp b/xfa/fxfa/app/xfa_ffpageview.cpp
index ce30d199d5..aef7a30226 100644
--- a/xfa/fxfa/app/xfa_ffpageview.cpp
+++ b/xfa/fxfa/app/xfa_ffpageview.cpp
@@ -432,3 +432,7 @@ CXFA_FFWidget* CXFA_FFTabOrderPageWidgetIterator::GetWidget(
   }
   return NULL;
 }
+
+CXFA_TabParam::CXFA_TabParam() : m_pWidget(NULL) {}
+
+CXFA_TabParam::~CXFA_TabParam() {}