Add observer for BAAnnots from Javascript

This Cl moves the observer code from the CPDFSDK_Widget up into the
CPDFSDK_Annot base class and then adds a second observer for CPDFSDK_BAAnnot
objects.

This allows us to attach an observer to the Annot javascript class which will
update its internal pointer to the BAAnnot if the BAAnnot is destroyed by
the CPDFSDK_PageView being destroyed.

BUG=chromium:642307

Review-Url: https://codereview.chromium.org/2306663002

1 files changed, 14 insertions, 0 deletions

diff --git a/fpdfsdk/include/cpdfsdk_annot.h b/fpdfsdk/include/cpdfsdk_annot.h
index 967226e9db..a43b8775db 100644
--- a/fpdfsdk/include/cpdfsdk_annot.h
+++ b/fpdfsdk/include/cpdfsdk_annot.h
@@ -23,9 +23,22 @@ class CPDFSDK_PageView;
 
 class CPDFSDK_Annot {
  public:
+  class Observer {
+   public:
+    explicit Observer(CPDFSDK_Annot** pWatchedPtr);
+    ~Observer();
+    void OnAnnotDestroyed();
+
+   private:
+    CPDFSDK_Annot** m_pWatchedPtr;
+  };
+
   explicit CPDFSDK_Annot(CPDFSDK_PageView* pPageView);
   virtual ~CPDFSDK_Annot();
 
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
 #ifdef PDF_ENABLE_XFA
   virtual FX_BOOL IsXFAField();
   virtual CXFA_FFWidget* GetXFAWidget() const;
@@ -57,6 +70,7 @@ class CPDFSDK_Annot {
   void SetSelected(FX_BOOL bSelected);
 
  protected:
+  std::set<Observer*> m_Observers;
   CPDFSDK_PageView* m_pPageView;
   FX_BOOL m_bSelected;
 };