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, 12 insertions, 0 deletions

diff --git a/core/fpdfapi/fpdf_page/cpdf_contentmarkdata.cpp b/core/fpdfapi/fpdf_page/cpdf_contentmarkdata.cpp
index 076e8ac521..256e266b04 100644
--- a/core/fpdfapi/fpdf_page/cpdf_contentmarkdata.cpp
+++ b/core/fpdfapi/fpdf_page/cpdf_contentmarkdata.cpp
@@ -9,13 +9,25 @@
 #include "core/fpdfapi/fpdf_parser/include/cpdf_dictionary.h"
 #include "third_party/base/stl_util.h"
 
+CPDF_ContentMarkData::CPDF_ContentMarkData() {}
+
 CPDF_ContentMarkData::CPDF_ContentMarkData(const CPDF_ContentMarkData& src)
     : m_Marks(src.m_Marks) {}
 
+CPDF_ContentMarkData::~CPDF_ContentMarkData() {}
+
 int CPDF_ContentMarkData::CountItems() const {
   return pdfium::CollectionSize<int>(m_Marks);
 }
 
+CPDF_ContentMarkItem& CPDF_ContentMarkData::GetItem(int index) {
+  return m_Marks[index];
+}
+
+const CPDF_ContentMarkItem& CPDF_ContentMarkData::GetItem(int index) const {
+  return m_Marks[index];
+}
+
 int CPDF_ContentMarkData::GetMCID() const {
   for (const auto& mark : m_Marks) {
     CPDF_ContentMarkItem::ParamType type = mark.GetParamType();