Make code compile with clang_use_chrome_plugin (part IV)

This change mainly contains files in fpdfsdk/ 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 plus removing an unused file and splitting
cxfa_eventparam out from fxfa.h

BUG=pdfium:469

Review-Url: https://codereview.chromium.org/2062313002
diff --git a/fpdfsdk/javascript/Field.h b/fpdfsdk/javascript/Field.h
index f5a7e1b..84bba68 100644
--- a/fpdfsdk/javascript/Field.h
+++ b/fpdfsdk/javascript/Field.h
@@ -54,8 +54,8 @@
 };
 
 struct CJS_DelayData {
-  CJS_DelayData(FIELD_PROP prop, int idx, const CFX_WideString& name)
-      : eProp(prop), nControlIndex(idx), sFieldName(name) {}
+  CJS_DelayData(FIELD_PROP prop, int idx, const CFX_WideString& name);
+  ~CJS_DelayData();
 
   FIELD_PROP eProp;
   int nControlIndex;