Change FXSYS_RGB() to FXSYS_BGR().

Also change it from a macro to a constexpr function.

Change-Id: I8b2bb42c45a23da6db136abdaee24132db4471c6
Reviewed-on: https://pdfium-review.googlesource.com/28579
Commit-Queue: dsinclair <dsinclair@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>
diff --git a/fpdfsdk/cpdfsdk_interform.cpp b/fpdfsdk/cpdfsdk_interform.cpp
index f4e22d7..9231951 100644
--- a/fpdfsdk/cpdfsdk_interform.cpp
+++ b/fpdfsdk/cpdfsdk_interform.cpp
@@ -46,6 +46,8 @@
 
 namespace {
 
+constexpr uint32_t kWhiteBGR = FXSYS_BGR(255, 255, 255);
+
 bool IsFormFieldTypeComboOrText(FormFieldType fieldType) {
   switch (fieldType) {
     case FormFieldType::kComboBox:
@@ -699,7 +701,7 @@
 
 void CPDFSDK_InterForm::RemoveAllHighLights() {
   std::fill(m_HighlightColor, m_HighlightColor + kFormFieldTypeCount,
-            FXSYS_RGB(255, 255, 255));
+            kWhiteBGR);
   std::fill(m_NeedsHighlight, m_NeedsHighlight + kFormFieldTypeCount, false);
 }
 
@@ -721,7 +723,7 @@
 
 FX_COLORREF CPDFSDK_InterForm::GetHighlightColor(FormFieldType fieldType) {
   if (fieldType == FormFieldType::kUnknown)
-    return FXSYS_RGB(255, 255, 255);
+    return kWhiteBGR;
 
 #ifdef PDF_ENABLE_XFA
   // For the XFA fields, we need to return the specific field type highlight