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, 2 insertions, 0 deletions

diff --git a/core/fpdfapi/fpdf_edit/cpdf_pagecontentgenerator.cpp b/core/fpdfapi/fpdf_edit/cpdf_pagecontentgenerator.cpp
index 20ae34349b..7ddc211671 100644
--- a/core/fpdfapi/fpdf_edit/cpdf_pagecontentgenerator.cpp
+++ b/core/fpdfapi/fpdf_edit/cpdf_pagecontentgenerator.cpp
@@ -31,6 +31,8 @@ CPDF_PageContentGenerator::CPDF_PageContentGenerator(CPDF_Page* pPage)
     InsertPageObject(pObj.get());
 }
 
+CPDF_PageContentGenerator::~CPDF_PageContentGenerator() {}
+
 FX_BOOL CPDF_PageContentGenerator::InsertPageObject(
     CPDF_PageObject* pPageObject) {
   return pPageObject && m_pageObjects.Add(pPageObject);