Add create note palette action.

ash/common/palette_delegate.h

Index: ash/common/palette_delegate.h
diff --git a/ash/common/palette_delegate.h b/ash/common/palette_delegate.h
index e167751e27d954113061d0d750b80efac401c833..34d0d11ad87e9c06d8a46959836a4ad04d893ac4 100644
--- a/ash/common/palette_delegate.h
+++ b/ash/common/palette_delegate.h
@@ -16,7 +16,11 @@ class PaletteDelegate {
  public:
   virtual ~PaletteDelegate() {}
 
-  // TODO(jdufault): This delegate will be implemented in later CLs.
+  // Create a new note.
+  virtual void CreateNote() = 0;
+
+  // Returns true if there is a note-taking application available.
+  virtual bool HasNoteApp() = 0;
 
  private:
   DISALLOW_ASSIGN(PaletteDelegate);