Merge to XFA: Clean up CPDF_AnnotList.

- Remove dead code
- Stop using CFX_PtrArray
- Mark more things const
- Fix style nits

TBR=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1425093003 .

(cherry picked from commit c88c42f317c0e94c4c7b98949bfe1a495aef07a9)

Review URL: https://codereview.chromium.org/1430803003 .
diff --git a/fpdfsdk/src/fpdfeditpage.cpp b/fpdfsdk/src/fpdfeditpage.cpp
index 8b4168f..531d372 100644
--- a/fpdfsdk/src/fpdfeditpage.cpp
+++ b/fpdfsdk/src/fpdfeditpage.cpp
@@ -280,7 +280,7 @@
   if (!pPage)
     return;
   CPDF_AnnotList AnnotList(pPage);
-  for (int i = 0; i < AnnotList.Count(); i++) {
+  for (size_t i = 0; i < AnnotList.Count(); ++i) {
     CPDF_Annot* pAnnot = AnnotList.GetAt(i);
     // transformAnnots Rectangle
     CPDF_Rect rect;