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, 8 insertions, 0 deletions

diff --git a/core/fpdfapi/fpdf_page/cpdf_tilingpattern.cpp b/core/fpdfapi/fpdf_page/cpdf_tilingpattern.cpp
index 0b1eeab9f4..f7370de0bc 100644
--- a/core/fpdfapi/fpdf_page/cpdf_tilingpattern.cpp
+++ b/core/fpdfapi/fpdf_page/cpdf_tilingpattern.cpp
@@ -24,6 +24,14 @@ CPDF_TilingPattern::CPDF_TilingPattern(CPDF_Document* pDoc,
 CPDF_TilingPattern::~CPDF_TilingPattern() {
 }
 
+CPDF_TilingPattern* CPDF_TilingPattern::AsTilingPattern() {
+  return this;
+}
+
+CPDF_ShadingPattern* CPDF_TilingPattern::AsShadingPattern() {
+  return nullptr;
+}
+
 FX_BOOL CPDF_TilingPattern::Load() {
   if (m_pForm)
     return TRUE;