Remove more unneeded STL #includes from headers.

Remove some variables named "string" to avoid false positives from the
linter.

Change-Id: I00a53e6970451fd0cea8ab2f8178183650ca00d2
Reviewed-on: https://pdfium-review.googlesource.com/42810
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
diff --git a/fxjs/cjs_field.cpp b/fxjs/cjs_field.cpp
index 1f39051..45baf61 100644
--- a/fxjs/cjs_field.cpp
+++ b/fxjs/cjs_field.cpp
@@ -2608,10 +2608,10 @@
   m_pJSDoc->AddDelayData(std::move(pNewData));
 }
 
-void CJS_Field::AddDelay_String(FIELD_PROP prop, const ByteString& string) {
+void CJS_Field::AddDelay_String(FIELD_PROP prop, const ByteString& str) {
   auto pNewData =
       pdfium::MakeUnique<CJS_DelayData>(prop, m_nFormControlIndex, m_FieldName);
-  pNewData->string = string;
+  pNewData->bytestring = str;
   m_pJSDoc->AddDelayData(std::move(pNewData));
 }
 
@@ -2644,7 +2644,7 @@
   switch (pData->eProp) {
     case FP_BORDERSTYLE:
       SetBorderStyle(pFormFillEnv, pData->sFieldName, pData->nControlIndex,
-                     pData->string);
+                     pData->bytestring);
       break;
     case FP_CURRENTVALUEINDICES:
       SetCurrentValueIndices(pFormFillEnv, pData->sFieldName,