Split off IPDF_SecurityHandler and CPDF_StandardSecurityHandler.

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index e238d31714e7eacfdb78116368e814e526282bd0..5d93a0c995d5a752e8b4e447ef831bfab2974413 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -248,6 +248,7 @@ static_library("fpdfapi") {
     "core/include/fpdfapi/fpdf_render.h",
     "core/include/fpdfapi/fpdf_resource.h",
     "core/include/fpdfapi/fpdf_serial.h",
+    "core/include/fpdfapi/ipdf_security_handler.h",
     "core/src/fpdfapi/fpdf_basic_module.cpp",
     "core/src/fpdfapi/fpdf_cmaps/CNS1/Adobe-CNS1-UCS2_5.cpp",
     "core/src/fpdfapi/fpdf_cmaps/CNS1/B5pc-H_0.cpp",
@@ -337,6 +338,8 @@ static_library("fpdfapi") {
     "core/src/fpdfapi/fpdf_parser/cpdf_document.cpp",
     "core/src/fpdfapi/fpdf_parser/cpdf_parser.cpp",
     "core/src/fpdfapi/fpdf_parser/cpdf_simple_parser.cpp",
+    "core/src/fpdfapi/fpdf_parser/cpdf_standard_security_handler.cpp",
+    "core/src/fpdfapi/fpdf_parser/cpdf_standard_security_handler.h",
     "core/src/fpdfapi/fpdf_parser/cpdf_syntax_parser.cpp",
     "core/src/fpdfapi/fpdf_parser/cpdf_syntax_parser.h",
     "core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp",