Remove always-"Off" argument from SetAppState()

Then simplify and rename as appropriate.

Change-Id: I67bef96ac31ae18a6fe85cd49eea68f8d3344700
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/79514
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>

fpdfsdk/cpdfsdk_appstream.cpp

diff --git a/fpdfsdk/cpdfsdk_appstream.cpp b/fpdfsdk/cpdfsdk_appstream.cpp
index 2945f41..1284439 100644
--- a/fpdfsdk/cpdfsdk_appstream.cpp
+++ b/fpdfsdk/cpdfsdk_appstream.cpp
@@ -1422,7 +1422,7 @@
 
   ByteString csAS = widget_->GetAppState();
   if (csAS.IsEmpty())
-    widget_->SetAppState("Off");
+    widget_->SetAppStateOff();
 }
 
 void CPDFSDK_AppStream::SetAsRadioButton() {
@@ -1554,7 +1554,7 @@
 
   ByteString csAS = widget_->GetAppState();
   if (csAS.IsEmpty())
-    widget_->SetAppState("Off");
+    widget_->SetAppStateOff();
 }
 
 void CPDFSDK_AppStream::SetAsComboBox(Optional<WideString> sValue) {

fpdfsdk/cpdfsdk_baannot.cpp

diff --git a/fpdfsdk/cpdfsdk_baannot.cpp b/fpdfsdk/cpdfsdk_baannot.cpp
index 72551ee..dc3f891 100644
--- a/fpdfsdk/cpdfsdk_baannot.cpp
+++ b/fpdfsdk/cpdfsdk_baannot.cpp
@@ -97,12 +97,9 @@
   return GetAnnotDict()->GetIntegerFor(pdfium::annotation::kF);
 }
 
-void CPDFSDK_BAAnnot::SetAppState(const ByteString& str) {
+void CPDFSDK_BAAnnot::SetAppStateOff() {
   CPDF_Dictionary* pDict = GetAnnotDict();
-  if (str.IsEmpty())
-    pDict->RemoveFor(pdfium::annotation::kAS);
-  else
-    pDict->SetNewFor<CPDF_String>(pdfium::annotation::kAS, str, false);
+  pDict->SetNewFor<CPDF_String>(pdfium::annotation::kAS, "Off", false);
 }
 
 ByteString CPDFSDK_BAAnnot::GetAppState() const {

fpdfsdk/cpdfsdk_baannot.h

diff --git a/fpdfsdk/cpdfsdk_baannot.h b/fpdfsdk/cpdfsdk_baannot.h
index df6f5f8..20eb2e6 100644
--- a/fpdfsdk/cpdfsdk_baannot.h
+++ b/fpdfsdk/cpdfsdk_baannot.h
@@ -50,7 +50,7 @@
   void SetFlags(uint32_t nFlags);
   uint32_t GetFlags() const;
 
-  void SetAppState(const ByteString& str);
+  void SetAppStateOff();
   ByteString GetAppState() const;
 
   void SetBorderWidth(int nWidth);