Fix bug #15365 with aborts in try_window_id.

 src/xdisp.c (try_window_id): Don't abort if cursor row could not be
 found (which can legitimately happen when the glyph row at the
 window start is disabled in the current_matrix.

src/ChangeLog

+2013-09-22  Eli Zaretskii  <eliz@gnu.org>
+
+	* xdisp.c (try_window_id): Don't abort if cursor row could not be
+	found (which can legitimately happen when the glyph row at the
+	window start is disabled in the current_matrix.  (Bug#15365)
+
 2013-09-22  Paul Eggert  <eggert@cs.ucla.edu>
 
 	Fix syntax.h bug introduced by recent INLINE change.

src/xdisp.c

@@ -17291,8 +17291,6 @@ try_window_id (struct window *w)
 	  row = row_containing_pos (w, PT, r0, NULL, 0);
 	  if (row)
 	    set_cursor_from_row (w, row, current_matrix, 0, 0, 0, 0);
-	  else
-	    emacs_abort ();
 	  return 1;
 	}
     }
@@ -17333,8 +17331,6 @@ try_window_id (struct window *w)
 	  row = row_containing_pos (w, PT, r0, NULL, 0);
 	  if (row)
 	    set_cursor_from_row (w, row, current_matrix, 0, 0, 0, 0);
-	  else
-	    emacs_abort ();
 	  return 2;
 	}
     }