Break xfa_parser_imp apart

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index 8e63c808e202f974e7458f6115f9740664ee29f2..7503b0cab1731a852ce9b785a3647e6508d11ca0 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1324,6 +1324,8 @@ if (pdf_enable_xfa) {
       "xfa/fxfa/parser/cxfa_corner.h",
       "xfa/fxfa/parser/cxfa_data.cpp",
       "xfa/fxfa/parser/cxfa_data.h",
+      "xfa/fxfa/parser/cxfa_document_parser.cpp",
+      "xfa/fxfa/parser/cxfa_document_parser.h",
       "xfa/fxfa/parser/cxfa_edge.h",
       "xfa/fxfa/parser/cxfa_event.cpp",
       "xfa/fxfa/parser/cxfa_event.h",
@@ -1346,6 +1348,8 @@ if (pdf_enable_xfa) {
       "xfa/fxfa/parser/cxfa_rectangle.h",
       "xfa/fxfa/parser/cxfa_script.cpp",
       "xfa/fxfa/parser/cxfa_script.h",
+      "xfa/fxfa/parser/cxfa_simple_parser.cpp",
+      "xfa/fxfa/parser/cxfa_simple_parser.h",
       "xfa/fxfa/parser/cxfa_stroke.cpp",
       "xfa/fxfa/parser/cxfa_stroke.h",
       "xfa/fxfa/parser/cxfa_submit.cpp",
@@ -1362,6 +1366,8 @@ if (pdf_enable_xfa) {
       "xfa/fxfa/parser/cxfa_valuearray.h",
       "xfa/fxfa/parser/cxfa_widgetdata.cpp",
       "xfa/fxfa/parser/cxfa_widgetdata.h",
+      "xfa/fxfa/parser/cxfa_xml_parser.cpp",
+      "xfa/fxfa/parser/cxfa_xml_parser.h",
       "xfa/fxfa/parser/xfa_basic_data.cpp",
       "xfa/fxfa/parser/xfa_basic_data_attributes.cpp",
       "xfa/fxfa/parser/xfa_basic_data_element_attributes.cpp",
@@ -1397,8 +1403,6 @@ if (pdf_enable_xfa) {
       "xfa/fxfa/parser/xfa_localevalue.h",
       "xfa/fxfa/parser/xfa_object.h",
       "xfa/fxfa/parser/xfa_object_imp.cpp",
-      "xfa/fxfa/parser/xfa_parser_imp.cpp",
-      "xfa/fxfa/parser/xfa_parser_imp.h",
       "xfa/fxfa/parser/xfa_script.h",
       "xfa/fxfa/parser/xfa_script_datawindow.cpp",
       "xfa/fxfa/parser/xfa_script_datawindow.h",
@@ -1537,7 +1541,7 @@ test("pdfium_embeddertests") {
     "testing/embedder_test.h",
     "testing/embedder_test_mock_delegate.h",
     "testing/embedder_test_timer_handling_delegate.h",
-    "xfa/fxfa/parser/xfa_parser_imp_embeddertest.cpp",
+    "xfa/fxfa/parser/cxfa_simple_parser_embeddertest.cpp",
   ]
   deps = [
     ":pdfium",