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, 7 insertions, 0 deletions

diff --git a/xfa/fxfa/app/xfa_ffapp.cpp b/xfa/fxfa/app/xfa_ffapp.cpp
index f2a6ad5e0d..5f2f1b9828 100644
--- a/xfa/fxfa/app/xfa_ffapp.cpp
+++ b/xfa/fxfa/app/xfa_ffapp.cpp
@@ -25,6 +25,9 @@ CXFA_FileRead::CXFA_FileRead(const CFX_ArrayTemplate<CPDF_Stream*>& streams) {
     acc.LoadAllData(streams[i]);
   }
 }
+
+CXFA_FileRead::~CXFA_FileRead() {}
+
 FX_FILESIZE CXFA_FileRead::GetSize() {
   uint32_t dwSize = 0;
   int32_t iCount = m_Data.GetSize();
@@ -64,6 +67,10 @@ FX_BOOL CXFA_FileRead::ReadBlock(void* buffer,
   return FALSE;
 }
 
+void CXFA_FileRead::Release() {
+  delete this;
+}
+
 CXFA_FFApp::CXFA_FFApp(IXFA_AppProvider* pProvider)
     : m_pDocHandler(nullptr),
       m_pFWLTheme(nullptr),