Split CPDF_PageObjectHolder off from CPDF_PageObjectList

Eventually, we're going to expose an iterator over
CPDF_PageObjectList that we don't want to be inherited by
the CPDF_PageObjectHolder sub-classes: page and form.

Also, the operations that the object holder performs dealing
with inquiring about masks and such seem beyond the scope of
what a list would provide.  Hence the "Holder" name.

R=thestig@chromium.org

Review URL: https://codereview.chromium.org/1701073002 .

5 files changed, 32 insertions, 31 deletions

diff --git a/fpdfsdk/src/fpdf_flatten.cpp b/fpdfsdk/src/fpdf_flatten.cpp
index 413b391eee..36b8319dca 100644
--- a/fpdfsdk/src/fpdf_flatten.cpp
+++ b/fpdfsdk/src/fpdf_flatten.cpp
@@ -42,9 +42,10 @@ FX_BOOL GetContentsRect(CPDF_Document* pDoc,
   pPDFPage->Load(pDoc, pDict, FALSE);
   pPDFPage->ParseContent(nullptr);
 
-  FX_POSITION pos = pPDFPage->GetFirstObjectPosition();
+  FX_POSITION pos = pPDFPage->GetPageObjectList()->GetHeadPosition();
   while (pos) {
-    CPDF_PageObject* pPageObject = pPDFPage->GetNextObject(pos);
+    CPDF_PageObject* pPageObject =
+        pPDFPage->GetPageObjectList()->GetNextObject(pos);
     if (!pPageObject)
       continue;
 
diff --git a/fpdfsdk/src/fpdfeditpage.cpp b/fpdfsdk/src/fpdfeditpage.cpp
index f964172d10..6d39cb100f 100644
--- a/fpdfsdk/src/fpdfeditpage.cpp
+++ b/fpdfsdk/src/fpdfeditpage.cpp
@@ -135,9 +135,9 @@ DLLEXPORT void STDCALL FPDFPage_InsertObject(FPDF_PAGE page,
   CPDF_PageObject* pPageObj = (CPDF_PageObject*)page_obj;
   if (!pPageObj)
     return;
-  FX_POSITION LastPersition = pPage->GetLastObjectPosition();
+  FX_POSITION LastPersition = pPage->GetPageObjectList()->GetTailPosition();
 
-  pPage->InsertObject(LastPersition, pPageObj);
+  pPage->GetPageObjectList()->InsertObject(LastPersition, pPageObj);
   switch (pPageObj->m_Type) {
     case FPDF_PAGEOBJ_PATH: {
       CPDF_PathObject* pPathObj = (CPDF_PathObject*)pPageObj;
@@ -177,7 +177,7 @@ DLLEXPORT int STDCALL FPDFPage_CountObject(FPDF_PAGE page) {
           "Page")) {
     return -1;
   }
-  return pPage->CountObjects();
+  return pPage->GetPageObjectList()->GetCount();
 }
 
 DLLEXPORT FPDF_PAGEOBJECT STDCALL FPDFPage_GetObject(FPDF_PAGE page,
@@ -188,7 +188,7 @@ DLLEXPORT FPDF_PAGEOBJECT STDCALL FPDFPage_GetObject(FPDF_PAGE page,
           "Page")) {
     return NULL;
   }
-  return pPage->GetObjectByIndex(index);
+  return pPage->GetPageObjectList()->GetObjectByIndex(index);
 }
 
 DLLEXPORT FPDF_BOOL STDCALL FPDFPage_HasTransparency(FPDF_PAGE page) {
diff --git a/fpdfsdk/src/fxedit/fxet_pageobjs.cpp b/fpdfsdk/src/fxedit/fxet_pageobjs.cpp
index 6cdcc84991..d54e4649db 100644
--- a/fpdfsdk/src/fxedit/fxet_pageobjs.cpp
+++ b/fpdfsdk/src/fxedit/fxet_pageobjs.cpp
@@ -409,7 +409,7 @@ void IFX_Edit::DrawRichEdit(CFX_RenderDevice* pDevice,
   pDevice->RestoreState();
 }
 
-static void AddRectToPageObjects(CPDF_PageObjectList* pPageObjs,
+static void AddRectToPageObjects(CPDF_PageObjectHolder* pPageObjs,
                                  FX_COLORREF crFill,
                                  const CPDF_Rect& rcFill) {
   CPDF_PathObject* pPathObj = new CPDF_PathObject;
@@ -425,18 +425,19 @@ static void AddRectToPageObjects(CPDF_PageObjectList* pPageObjs,
 
   pPathObj->m_FillType = FXFILL_ALTERNATE;
   pPathObj->m_bStroke = FALSE;
-
-  pPageObjs->InsertObject(pPageObjs->GetLastObjectPosition(), pPathObj);
+  pPageObjs->GetPageObjectList()->InsertObject(
+      pPageObjs->GetPageObjectList()->GetTailPosition(), pPathObj);
 }
 
-static CPDF_TextObject* AddTextObjToPageObjects(CPDF_PageObjectList* pPageObjs,
-                                                FX_COLORREF crText,
-                                                CPDF_Font* pFont,
-                                                FX_FLOAT fFontSize,
-                                                FX_FLOAT fCharSpace,
-                                                int32_t nHorzScale,
-                                                const CPDF_Point& point,
-                                                const CFX_ByteString& text) {
+static CPDF_TextObject* AddTextObjToPageObjects(
+    CPDF_PageObjectHolder* pPageObjs,
+    FX_COLORREF crText,
+    CPDF_Font* pFont,
+    FX_FLOAT fFontSize,
+    FX_FLOAT fCharSpace,
+    int32_t nHorzScale,
+    const CPDF_Point& point,
+    const CFX_ByteString& text) {
   CPDF_TextObject* pTxtObj = new CPDF_TextObject;
 
   CPDF_TextStateData* pTextStateData = pTxtObj->m_TextState.GetModify();
@@ -461,14 +462,14 @@ static CPDF_TextObject* AddTextObjToPageObjects(CPDF_PageObjectList* pPageObjs,
 
   pTxtObj->SetPosition(point.x, point.y);
   pTxtObj->SetText(text);
-
-  pPageObjs->InsertObject(pPageObjs->GetLastObjectPosition(), pTxtObj);
+  pPageObjs->GetPageObjectList()->InsertObject(
+      pPageObjs->GetPageObjectList()->GetTailPosition(), pTxtObj);
 
   return pTxtObj;
 }
 
 void IFX_Edit::GeneratePageObjects(
-    CPDF_PageObjectList* pPageObjects,
+    CPDF_PageObjectHolder* pPageObjects,
     IFX_Edit* pEdit,
     const CPDF_Point& ptOffset,
     const CPVT_WordRange* pRange,
@@ -532,7 +533,7 @@ void IFX_Edit::GeneratePageObjects(
 }
 
 void IFX_Edit::GenerateRichPageObjects(
-    CPDF_PageObjectList* pPageObjects,
+    CPDF_PageObjectHolder* pPageObjects,
     IFX_Edit* pEdit,
     const CPDF_Point& ptOffset,
     const CPVT_WordRange* pRange,
@@ -624,7 +625,7 @@ void IFX_Edit::GenerateRichPageObjects(
   }
 }
 
-void IFX_Edit::GenerateUnderlineObjects(CPDF_PageObjectList* pPageObjects,
+void IFX_Edit::GenerateUnderlineObjects(CPDF_PageObjectHolder* pPageObjects,
                                         IFX_Edit* pEdit,
                                         const CPDF_Point& ptOffset,
                                         const CPVT_WordRange* pRange,
diff --git a/fpdfsdk/src/javascript/Document.cpp b/fpdfsdk/src/javascript/Document.cpp
index 0bd754af76..e869e72310 100644
--- a/fpdfsdk/src/javascript/Document.cpp
+++ b/fpdfsdk/src/javascript/Document.cpp
@@ -1380,14 +1380,12 @@ FX_BOOL Document::getPageNthWord(IJS_Context* cc,
   page.Load(pDocument, pPageDict);
   page.ParseContent(nullptr);
 
-  FX_POSITION pos = page.GetFirstObjectPosition();
-
   int nWords = 0;
-
   CFX_WideString swRet;
-
+  FX_POSITION pos = page.GetPageObjectList()->GetHeadPosition();
   while (pos) {
-    if (CPDF_PageObject* pPageObj = page.GetNextObject(pos)) {
+    if (CPDF_PageObject* pPageObj =
+            page.GetPageObjectList()->GetNextObject(pos)) {
       if (pPageObj->m_Type == CPDF_PageObject::TEXT) {
         int nObjWords = CountWords((CPDF_TextObject*)pPageObj);
 
@@ -1444,9 +1442,10 @@ FX_BOOL Document::getPageNumWords(IJS_Context* cc,
   page.ParseContent(nullptr);
 
   int nWords = 0;
-  FX_POSITION pos = page.GetFirstObjectPosition();
+  FX_POSITION pos = page.GetPageObjectList()->GetHeadPosition();
   while (pos) {
-    if (CPDF_PageObject* pPageObj = page.GetNextObject(pos)) {
+    if (CPDF_PageObject* pPageObj =
+            page.GetPageObjectList()->GetNextObject(pos)) {
       if (pPageObj->m_Type == CPDF_PageObject::TEXT) {
         CPDF_TextObject* pTextObj = (CPDF_TextObject*)pPageObj;
         nWords += CountWords(pTextObj);
diff --git a/fpdfsdk/src/pdfwindow/PWL_Edit.cpp b/fpdfsdk/src/pdfwindow/PWL_Edit.cpp
index cbef23cc19..057cb4191e 100644
--- a/fpdfsdk/src/pdfwindow/PWL_Edit.cpp
+++ b/fpdfsdk/src/pdfwindow/PWL_Edit.cpp
@@ -1168,7 +1168,7 @@ CPVT_WordRange CPWL_Edit::GetSameWordsRange(const CPVT_WordPlace& place,
 }
 
 void CPWL_Edit::GeneratePageObjects(
-    CPDF_PageObjectList* pPageObjects,
+    CPDF_PageObjectHolder* pPageObjects,
     const CPDF_Point& ptOffset,
     CFX_ArrayTemplate<CPDF_TextObject*>& ObjArray) {
   IFX_Edit::GeneratePageObjects(
@@ -1177,7 +1177,7 @@ void CPWL_Edit::GeneratePageObjects(
       ObjArray);
 }
 
-void CPWL_Edit::GeneratePageObjects(CPDF_PageObjectList* pPageObjects,
+void CPWL_Edit::GeneratePageObjects(CPDF_PageObjectHolder* pPageObjects,
                                     const CPDF_Point& ptOffset) {
   CFX_ArrayTemplate<CPDF_TextObject*> ObjArray;
   IFX_Edit::GeneratePageObjects(