Merge to XFA: Disentangle fpdfsave_embeddertest's FPDF_FILEWRITE.

Original Review URL: https://codereview.chromium.org/1561303002 .
(cherry picked from commit 5dc13d7858f9caf58b0e12f38823300a739302e2)

TBR=thestig@chromium.org

Review URL: https://codereview.chromium.org/1569973002 .

2 files changed, 34 insertions, 0 deletions

diff --git a/testing/test_support.cpp b/testing/test_support.cpp
index 96e01c5b01..da5ea7e9ee 100644
--- a/testing/test_support.cpp
+++ b/testing/test_support.cpp
@@ -172,3 +172,21 @@ int TestLoader::GetBlock(void* param,
   memcpy(pBuf, pLoader->m_pBuf + pos, size);
   return 1;
 }
+
+TestSaver::TestSaver() {
+  FPDF_FILEWRITE::version = 1;
+  FPDF_FILEWRITE::WriteBlock = WriteBlockCallback;
+}
+
+void TestSaver::ClearString() {
+  m_String.clear();
+}
+
+// static
+int TestSaver::WriteBlockCallback(FPDF_FILEWRITE* pFileWrite,
+                                  const void* data,
+                                  unsigned long size) {
+  TestSaver* pThis = static_cast<TestSaver*>(pFileWrite);
+  pThis->m_String.append(static_cast<const char*>(data), size);
+  return 1;
+}
diff --git a/testing/test_support.h b/testing/test_support.h
index 945704194d..f59d5440e7 100644
--- a/testing/test_support.h
+++ b/testing/test_support.h
@@ -10,6 +10,7 @@
 #include <string>
 
 #include "public/fpdfview.h"
+#include "public/fpdf_save.h"
 
 #ifdef PDF_ENABLE_V8
 #include "v8/include/v8.h"
@@ -62,4 +63,19 @@ class TestLoader {
   const size_t m_Len;
 };
 
+class TestSaver : public FPDF_FILEWRITE {
+ public:
+  TestSaver();
+
+  void ClearString();
+  const std::string& GetString() const { return m_String; }
+
+ private:
+  static int WriteBlockCallback(FPDF_FILEWRITE* pFileWrite,
+                                const void* data,
+                                unsigned long size);
+
+  std::string m_String;
+};
+
 #endif  // TESTING_EMBEDDER_TEST_SUPPORT_H_