Make code compile with clang_use_chrome_plugin (part I)

This change contains files in core/fpdfapi 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/2060973002

1 files changed, 4 insertions, 0 deletions

diff --git a/core/fpdfapi/fpdf_page/cpdf_graphicstates.cpp b/core/fpdfapi/fpdf_page/cpdf_graphicstates.cpp
index 9c540941ce..fc054caf21 100644
--- a/core/fpdfapi/fpdf_page/cpdf_graphicstates.cpp
+++ b/core/fpdfapi/fpdf_page/cpdf_graphicstates.cpp
@@ -6,6 +6,10 @@
 
 #include "core/fpdfapi/fpdf_page/cpdf_graphicstates.h"
 
+CPDF_GraphicStates::CPDF_GraphicStates() {}
+
+CPDF_GraphicStates::~CPDF_GraphicStates() {}
+
 void CPDF_GraphicStates::DefaultStates() {
   m_ColorState.New()->Default();
 }