Cleanup fsdk_define methods

This CL collects the various fsdk_define methods into a fsdk_define.cpp
class. Methods only used in one place are moved into the appropriate
anonymous namespaces.

Change-Id: I75bfc7e8fe20711106fcf9821adeb41d69bf5848
Reviewed-on: https://pdfium-review.googlesource.com/29310
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>
diff --git a/fpdfsdk/fpdfeditimg.cpp b/fpdfsdk/fpdfeditimg.cpp
index 335c152..a98a61f 100644
--- a/fpdfsdk/fpdfeditimg.cpp
+++ b/fpdfsdk/fpdfeditimg.cpp
@@ -14,6 +14,7 @@
 #include "core/fpdfapi/parser/cpdf_array.h"
 #include "core/fpdfapi/parser/cpdf_name.h"
 #include "core/fpdfapi/render/cpdf_dibsource.h"
+#include "fpdfsdk/cpdfsdk_customaccess.h"
 #include "fpdfsdk/fsdk_define.h"
 #include "third_party/base/ptr_util.h"
 
@@ -43,6 +44,11 @@
 static_assert(PDFCS_PATTERN == FPDF_COLORSPACE_PATTERN,
               "PDFCS_PATTERN value mismatch");
 
+RetainPtr<IFX_SeekableReadStream> MakeSeekableReadStream(
+    FPDF_FILEACCESS* pFileAccess) {
+  return pdfium::MakeRetain<CPDFSDK_CustomAccess>(pFileAccess);
+}
+
 bool LoadJpegHelper(FPDF_PAGE* pages,
                     int nCount,
                     FPDF_PAGEOBJECT image_object,