Re-introduce FWL_STATE_PSB_Default definition.

Once upon a time, there was a
  #define FWL_STATE_PSB_Default (1 << (FWL_WGTSTATE_MAX + 2))

that we removed because the definition was never used. However,
it turns out there were places where the equivalent expression
  (1 << (FWL_WGTSTATE_MAX + 2))

was used in conditionals, so restore the value, and use it there.

On the other hand, there doesn't appear to be a way to actually
set this value, but since the style extension field is overloaded
in all sorts of strange ways, we can't be 100% sure that this is
dead code as a result.

Change-Id: Iab2158cfdc672a11b50bcd9b0d7ae5d7f47d8af7
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/83191
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>

xfa/fwl/cfwl_pushbutton.h

diff --git a/xfa/fwl/cfwl_pushbutton.h b/xfa/fwl/cfwl_pushbutton.h
index 4b8998c..341a4b4 100644
--- a/xfa/fwl/cfwl_pushbutton.h
+++ b/xfa/fwl/cfwl_pushbutton.h
@@ -11,6 +11,7 @@
 
 #define FWL_STATE_PSB_Hovered (1 << FWL_STATE_WGT_MAX)
 #define FWL_STATE_PSB_Pressed (1 << (FWL_STATE_WGT_MAX + 1))
+#define FWL_STATE_PSB_Default (1 << (FWL_STATE_WGT_MAX + 2))
 
 class CFWL_MessageKey;
 class CFWL_MessageMouse;

xfa/fwl/cfwl_widgetmgr.cpp

diff --git a/xfa/fwl/cfwl_widgetmgr.cpp b/xfa/fwl/cfwl_widgetmgr.cpp
index bed8e41..807dbc7 100644
--- a/xfa/fwl/cfwl_widgetmgr.cpp
+++ b/xfa/fwl/cfwl_widgetmgr.cpp
@@ -11,6 +11,7 @@
 #include "xfa/fwl/cfwl_app.h"
 #include "xfa/fwl/cfwl_message.h"
 #include "xfa/fwl/cfwl_notedriver.h"
+#include "xfa/fwl/cfwl_pushbutton.h"
 
 CFWL_WidgetMgr::CFWL_WidgetMgr(AdapterIface* pAdapter, CFWL_App* pApp)
     : m_pAdapter(pAdapter), m_pApp(pApp) {
@@ -134,15 +135,15 @@
 }
 
 CFWL_Widget* CFWL_WidgetMgr::GetDefaultButton(CFWL_Widget* pParent) const {
-  if ((pParent->GetClassID() == FWL_Type::PushButton) &&
-      (pParent->GetStates() & (1 << (FWL_STATE_WGT_MAX + 2)))) {
+  if (pParent->GetClassID() == FWL_Type::PushButton &&
+      (pParent->GetStates() & FWL_STATE_PSB_Default)) {
     return pParent;
   }
 
   CFWL_Widget* child = GetFirstChildWidget(pParent);
   while (child) {
-    if ((child->GetClassID() == FWL_Type::PushButton) &&
-        (child->GetStates() & (1 << (FWL_STATE_WGT_MAX + 2)))) {
+    if (child->GetClassID() == FWL_Type::PushButton &&
+        (child->GetStates() & FWL_STATE_PSB_Default)) {
       return child;
     }
     if (CFWL_Widget* find = GetDefaultButton(child))