Move xfa_basic_imp to cxfa_widetextread.

This Cl splits out the CXFA_WideTextRead class into it's own file. The helper
methods have been moved into xfa_utils.cpp and their pre-declarations into
xfa_utils.h.

Review-Url: https://codereview.chromium.org/2165993002
diff --git a/BUILD.gn b/BUILD.gn
index f824163..996f7be 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1383,6 +1383,8 @@
       "xfa/fxfa/parser/cxfa_line.h",
       "xfa/fxfa/parser/cxfa_margin.cpp",
       "xfa/fxfa/parser/cxfa_margin.h",
+      "xfa/fxfa/parser/cxfa_measurement.cpp",
+      "xfa/fxfa/parser/cxfa_measurement.h",
       "xfa/fxfa/parser/cxfa_node.cpp",
       "xfa/fxfa/parser/cxfa_nodehelper.cpp",
       "xfa/fxfa/parser/cxfa_nodehelper.h",
@@ -1416,6 +1418,8 @@
       "xfa/fxfa/parser/cxfa_value.h",
       "xfa/fxfa/parser/cxfa_valuearray.cpp",
       "xfa/fxfa/parser/cxfa_valuearray.h",
+      "xfa/fxfa/parser/cxfa_widetextread.cpp",
+      "xfa/fxfa/parser/cxfa_widetextread.h",
       "xfa/fxfa/parser/cxfa_widgetdata.cpp",
       "xfa/fxfa/parser/cxfa_widgetdata.h",
       "xfa/fxfa/parser/cxfa_xml_parser.cpp",
@@ -1428,8 +1432,6 @@
       "xfa/fxfa/parser/xfa_basic_data_element_script.cpp",
       "xfa/fxfa/parser/xfa_basic_data_enum.cpp",
       "xfa/fxfa/parser/xfa_basic_data_packets.cpp",
-      "xfa/fxfa/parser/xfa_basic_imp.cpp",
-      "xfa/fxfa/parser/xfa_basic_imp.h",
       "xfa/fxfa/parser/xfa_doclayout.h",
       "xfa/fxfa/parser/xfa_document.h",
       "xfa/fxfa/parser/xfa_document_datamerger_imp.cpp",