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_imageobject.cpp b/core/fpdfapi/fpdf_page/cpdf_imageobject.cpp
index 6203d56273..e2defa8054 100644
--- a/core/fpdfapi/fpdf_page/cpdf_imageobject.cpp
+++ b/core/fpdfapi/fpdf_page/cpdf_imageobject.cpp
@@ -33,11 +33,27 @@ CPDF_ImageObject* CPDF_ImageObject::Clone() const {
   return obj;
 }
 
+CPDF_PageObject::Type CPDF_ImageObject::GetType() const {
+  return IMAGE;
+}
+
 void CPDF_ImageObject::Transform(const CFX_Matrix& matrix) {
   m_Matrix.Concat(matrix);
   CalcBoundingBox();
 }
 
+bool CPDF_ImageObject::IsImage() const {
+  return true;
+}
+
+CPDF_ImageObject* CPDF_ImageObject::AsImage() {
+  return this;
+}
+
+const CPDF_ImageObject* CPDF_ImageObject::AsImage() const {
+  return this;
+}
+
 void CPDF_ImageObject::CalcBoundingBox() {
   m_Left = m_Bottom = 0;
   m_Right = m_Top = 1.0f;