[orca] Prefer line presentation if previous review object had no string

[Joanmarie Diggs <joanied src gnome org>]

commit be67d8531ed20c25b0765009f2677924b4670d50
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Tue Jul 9 10:25:04 2019 -0400

    Prefer line presentation if previous review object had no string

 src/orca/mouse_review.py | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)
---
diff --git a/src/orca/mouse_review.py b/src/orca/mouse_review.py
index 5bfb914ba..8fde68564 100644
--- a/src/orca/mouse_review.py
+++ b/src/orca/mouse_review.py
@@ -114,6 +114,11 @@ class _StringContext:
 
         return self._boundingBox
 
+    def getString(self):
+        """Returns the string associated with this context."""
+
+        return self._string
+
     def present(self):
         """Presents this context to the user."""
 
@@ -244,6 +249,11 @@ class _ItemContext:
 
         return x, y, width, height
 
+    def getString(self):
+        """Returns the string associated with this context."""
+
+        return self._string.getString()
+
     def getTime(self):
         """Returns the time associated with this context."""
 
@@ -501,7 +511,7 @@ class MouseReviewer:
 
         boundary = None
         x, y, width, height = self._currentMouseOver.getBoundingBox()
-        if y <= pY <= y + height:
+        if y <= pY <= y + height and self._currentMouseOver.getString():
             boundary = pyatspi.TEXT_BOUNDARY_WORD_START
         elif obj == self._currentMouseOver.getObject():
             boundary = pyatspi.TEXT_BOUNDARY_LINE_START