Rename IPDF_FormNotify to CPDF_InteractiveForm::NotifierIface

Associate the interface with the class that tracks/uses it. In
some ideal world, the IXXX_* classes would have multiple concrete
implementations from which to select and the *Iface classes would
exist for layering.

Change-Id: Ic78fce2200cbd00bf27fa726b4527f39d2b373e0
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/59790
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
diff --git a/fpdfsdk/cpdfsdk_interactiveform.cpp b/fpdfsdk/cpdfsdk_interactiveform.cpp
index 2f888b4..9e7c548 100644
--- a/fpdfsdk/cpdfsdk_interactiveform.cpp
+++ b/fpdfsdk/cpdfsdk_interactiveform.cpp
@@ -115,8 +115,7 @@
     : m_pFormFillEnv(pFormFillEnv),
       m_pInteractiveForm(pdfium::MakeUnique<CPDF_InteractiveForm>(
           m_pFormFillEnv->GetPDFDocument())) {
-  ASSERT(m_pFormFillEnv);
-  m_pInteractiveForm->SetFormNotify(this);
+  m_pInteractiveForm->SetNotifierIface(this);
   RemoveAllHighLights();
 }