Create CPWL_AppStream.

This CL creates a CPWL_AppStream and consolidates app stream generation
code from CPDFSDK_Widget, CPDFSDK_BAAnnot and CPWL_Utils. The remaining
app stream code from CPWL_Utils will be cleaned up in a future CL.

Change-Id: I20cfdec09a351bd509241d2c667a182fba84b0c1
Reviewed-on: https://pdfium-review.googlesource.com/8310
Commit-Queue: dsinclair <dsinclair@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
diff --git a/fpdfsdk/cpdfsdk_baannot.h b/fpdfsdk/cpdfsdk_baannot.h
index 6c9ae06..18d25a1 100644
--- a/fpdfsdk/cpdfsdk_baannot.h
+++ b/fpdfsdk/cpdfsdk_baannot.h
@@ -36,6 +36,8 @@
   CPDF_Dictionary* GetAnnotDict() const;
   CPDF_Annot* GetPDFPopupAnnot() const;
 
+  CPDF_Dictionary* GetAPDict() const;
+
   void SetContents(const CFX_WideString& sContents);
   CFX_WideString GetContents() const;
 
@@ -88,12 +90,6 @@
 
   void ClearCachedAP();
 
-  void WriteAppearance(const CFX_ByteString& sAPType,
-                       const CFX_FloatRect& rcBBox,
-                       const CFX_Matrix& matrix,
-                       const CFX_ByteString& sContents,
-                       const CFX_ByteString& sAPState = "");
-
   void SetOpenState(bool bState);
 
  protected: