Move CPDFSDK_FormFillEnvironment::Is{SHIFT,CTRL,ALT}KeyDown to CPWL_Wnd

Removes an include of top-level fpdfsdk/ in fpdfsdk/pwl at the expense
of having another public/fwl_event.h include in cpwl_wnd.h (there are
several pre-existing instances of this public file used in pwl/).

In turn, fix some IWYU exposed by the change.

Change-Id: I1bc299f565aed4b4494bc4b969e5ad27aeb6263b
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/58613
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
diff --git a/fpdfsdk/cpdfsdk_annothandlermgr.cpp b/fpdfsdk/cpdfsdk_annothandlermgr.cpp
index b1a31fe..f4807b6 100644
--- a/fpdfsdk/cpdfsdk_annothandlermgr.cpp
+++ b/fpdfsdk/cpdfsdk_annothandlermgr.cpp
@@ -19,6 +19,7 @@
 #include "fpdfsdk/cpdfsdk_pageview.h"
 #include "fpdfsdk/cpdfsdk_widget.h"
 #include "fpdfsdk/cpdfsdk_widgethandler.h"
+#include "fpdfsdk/pwl/cpwl_wnd.h"
 #include "public/fpdf_fwlevent.h"
 #include "third_party/base/ptr_util.h"
 
@@ -225,16 +226,15 @@
 bool CPDFSDK_AnnotHandlerMgr::Annot_OnKeyDown(CPDFSDK_Annot* pAnnot,
                                               int nKeyCode,
                                               int nFlag) {
-  if (CPDFSDK_FormFillEnvironment::IsCTRLKeyDown(nFlag) ||
-      CPDFSDK_FormFillEnvironment::IsALTKeyDown(nFlag)) {
+  if (CPWL_Wnd::IsCTRLKeyDown(nFlag) || CPWL_Wnd::IsALTKeyDown(nFlag)) {
     return GetAnnotHandler(pAnnot)->OnKeyDown(pAnnot, nKeyCode, nFlag);
   }
   ObservedPtr<CPDFSDK_Annot> pObservedAnnot(pAnnot);
   CPDFSDK_PageView* pPage = pAnnot->GetPageView();
   CPDFSDK_Annot* pFocusAnnot = pPage->GetFocusAnnot();
   if (pFocusAnnot && (nKeyCode == FWL_VKEY_Tab)) {
-    ObservedPtr<CPDFSDK_Annot> pNext(GetNextAnnot(
-        pFocusAnnot, !CPDFSDK_FormFillEnvironment::IsSHIFTKeyDown(nFlag)));
+    ObservedPtr<CPDFSDK_Annot> pNext(
+        GetNextAnnot(pFocusAnnot, !CPWL_Wnd::IsSHIFTKeyDown(nFlag)));
     if (pNext && pNext.Get() != pFocusAnnot) {
       pPage->GetFormFillEnv()->SetFocusAnnot(&pNext);
       return true;