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, 16 insertions, 0 deletions

diff --git a/core/fpdfapi/fpdf_page/cpdf_shadingobject.cpp b/core/fpdfapi/fpdf_page/cpdf_shadingobject.cpp
index de84f29865..b2eb5e642c 100644
--- a/core/fpdfapi/fpdf_page/cpdf_shadingobject.cpp
+++ b/core/fpdfapi/fpdf_page/cpdf_shadingobject.cpp
@@ -30,6 +30,10 @@ CPDF_ShadingObject* CPDF_ShadingObject::Clone() const {
   return obj;
 }
 
+CPDF_PageObject::Type CPDF_ShadingObject::GetType() const {
+  return SHADING;
+}
+
 void CPDF_ShadingObject::Transform(const CFX_Matrix& matrix) {
   if (!m_ClipPath.IsNull()) {
     m_ClipPath.GetModify();
@@ -43,6 +47,18 @@ void CPDF_ShadingObject::Transform(const CFX_Matrix& matrix) {
   }
 }
 
+bool CPDF_ShadingObject::IsShading() const {
+  return true;
+}
+
+CPDF_ShadingObject* CPDF_ShadingObject::AsShading() {
+  return this;
+}
+
+const CPDF_ShadingObject* CPDF_ShadingObject::AsShading() const {
+  return this;
+}
+
 void CPDF_ShadingObject::CalcBoundingBox() {
   if (m_ClipPath.IsNull()) {
     return;