Add ObservedPtrs to catch issues in SaveData

BUG=chromium:756427

Change-Id: I90c7065ec5a467cb954cdf3e1d6954a0b0655d4e
Reviewed-on: https://pdfium-review.googlesource.com/15630
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>

2 files changed, 12 insertions, 6 deletions

diff --git a/fpdfsdk/formfiller/cffl_interactiveformfiller.cpp b/fpdfsdk/formfiller/cffl_interactiveformfiller.cpp
index 70d3990ea3..fb1afe94b4 100644
--- a/fpdfsdk/formfiller/cffl_interactiveformfiller.cpp
+++ b/fpdfsdk/formfiller/cffl_interactiveformfiller.cpp
@@ -672,9 +672,10 @@ void CFFL_InteractiveFormFiller::OnCalculate(CPDFSDK_Annot::ObservedPtr* pAnnot,
     return;
 
   CPDFSDK_Widget* pWidget = static_cast<CPDFSDK_Widget*>(pAnnot->Get());
-  ASSERT(pWidget);
-  CPDFSDK_InterForm* pInterForm = pPageView->GetFormFillEnv()->GetInterForm();
-  pInterForm->OnCalculate(pWidget->GetFormField());
+  if (pWidget) {
+    CPDFSDK_InterForm* pInterForm = pPageView->GetFormFillEnv()->GetInterForm();
+    pInterForm->OnCalculate(pWidget->GetFormField());
+  }
   m_bNotifying = false;
 }
 
diff --git a/fpdfsdk/formfiller/cffl_textfield.cpp b/fpdfsdk/formfiller/cffl_textfield.cpp
index 76434a5216..4174ae4179 100644
--- a/fpdfsdk/formfiller/cffl_textfield.cpp
+++ b/fpdfsdk/formfiller/cffl_textfield.cpp
@@ -139,10 +139,15 @@ void CFFL_TextField::SaveData(CPDFSDK_PageView* pPageView) {
   WideString sOldValue = m_pWidget->GetValue();
   WideString sNewValue = pWnd->GetText();
 
+  CPDFSDK_Widget::ObservedPtr observed_widget(m_pWidget.Get());
+  CFFL_TextField::ObservedPtr observed_this(this);
   m_pWidget->SetValue(sNewValue, false);
-  m_pWidget->ResetFieldAppearance(true);
-  m_pWidget->UpdateField();
-  SetChangeMark();
+  if (observed_widget)
+    m_pWidget->ResetFieldAppearance(true);
+  if (observed_widget)
+    m_pWidget->UpdateField();
+  if (observed_this)
+    SetChangeMark();
 }
 
 void CFFL_TextField::GetActionData(CPDFSDK_PageView* pPageView,