[orca] Filter out duplicate clipboard contents changed notifications

[Joanmarie Diggs <joanied src gnome org>]

commit 5eba5318e427943af5019ab7df3b180c970f0bf4
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Tue Oct 8 15:22:25 2019 -0400

    Filter out duplicate clipboard contents changed notifications

 src/orca/script_utilities.py | 7 +++++++
 1 file changed, 7 insertions(+)
---
diff --git a/src/orca/script_utilities.py b/src/orca/script_utilities.py
index ac9b085fb..d376758ab 100644
--- a/src/orca/script_utilities.py
+++ b/src/orca/script_utilities.py
@@ -66,6 +66,7 @@ _settingsManager = settings_manager.getManager()
 class Utilities:
 
     _desktop = pyatspi.Registry.getDesktop(0)
+    _last_clipboard_update = time.time()
 
     EMBEDDED_OBJECT_CHARACTER = '\ufffc'
     ZERO_WIDTH_NO_BREAK_SPACE = '\ufeff'
@@ -4638,6 +4639,12 @@ class Utilities:
         if not script:
             return
 
+        if time.time() - Utilities._last_clipboard_update < 0.05:
+            msg = "INFO: Clipboard contents change notification believed to be duplicate"
+            debug.println(debug.LEVEL_INFO, msg, True)
+            return
+
+        Utilities._last_clipboard_update = time.time()
         script.onClipboardContentsChanged(*args)
 
     def connectToClipboard(self):