Add public APIs for undo / redo in forms.

Add FORM_CanUndo(), FORM_CanRedo(), FORM_Undo(), and FORM_Redo().

BUG=chromium:764260

Change-Id: I1d9ea67152d9b35d9b8e1d7ef7d019706fdfa30a
Reviewed-on: https://pdfium-review.googlesource.com/30872
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>

1 files changed, 6 insertions, 8 deletions

diff --git a/fpdfsdk/pwl/cpwl_edit_ctrl.cpp b/fpdfsdk/pwl/cpwl_edit_ctrl.cpp
index 5e2f7acda6..579a587175 100644
--- a/fpdfsdk/pwl/cpwl_edit_ctrl.cpp
+++ b/fpdfsdk/pwl/cpwl_edit_ctrl.cpp
@@ -401,22 +401,20 @@ void CPWL_EditCtrl::Backspace() {
     m_pEdit->Backspace();
 }
 
-bool CPWL_EditCtrl::CanUndo() const {
+bool CPWL_EditCtrl::CanUndo() {
   return !IsReadOnly() && m_pEdit->CanUndo();
 }
 
-bool CPWL_EditCtrl::CanRedo() const {
+bool CPWL_EditCtrl::CanRedo() {
   return !IsReadOnly() && m_pEdit->CanRedo();
 }
 
-void CPWL_EditCtrl::Redo() {
-  if (CanRedo())
-    m_pEdit->Redo();
+bool CPWL_EditCtrl::Undo() {
+  return CanUndo() && m_pEdit->Undo();
 }
 
-void CPWL_EditCtrl::Undo() {
-  if (CanUndo())
-    m_pEdit->Undo();
+bool CPWL_EditCtrl::Redo() {
+  return CanRedo() && m_pEdit->Redo();
 }
 
 int32_t CPWL_EditCtrl::GetCharSet() const {