[Patch] improve performance when retrieving history

[GerdP]

What steps will reproduce the problem?

1. Start JOSM with --debug
2. Open URL ​https://www.openstreetmap.org/changeset/66843961
3. Look at the debug messages

What is the expected result?

No calls of GET ​https://api.openstreetmap.org/api/0.6/changesets?changesets

What happens instead?

Note that JOSM downloads a lot of changeset data for each object

GET https://api.openstreetmap.org/api/0.6/node/2087192798/history -> 200
...
GET https://api.openstreetmap.org/api/0.6/changesets?changesets=45597783,15351356,14450647 -> 200 (687 B)
...
GET https://api.openstreetmap.org/api/0.6/node/6245181047/history -> 200
...
GET https://api.openstreetmap.org/api/0.6/changesets?changesets=66748602 -> 200 (439 B)

The data retrieved with the GET https://api.openstreetmap.org/api/0.6/changesets?changesets is not used.

Please provide any additional information below. Attach a screenshot if possible.

The same problem occurs with the undelete plugin. Without these calls both acions are much faster.

Build-Date:2019-02-02 09:47:56
Revision:14756
Is-Local-Build:true

Identification: JOSM/1.5 (14756 SVN en) Windows 10 64-Bit
OS Build number: Windows 10 Home 1803 (17134)
Memory Usage: 572 MB / 1753 MB (367 MB allocated, but free)
Java version: 1.8.0_191-b12, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
Screen: \Display0 1920x1080
Maximum Screen Size: 1920x1080
VM arguments: [-agentlib:jdwp=transport=dt_socket,suspend=y,address=localhost:64582, -ea, -Dfile.encoding=UTF-8]
Program arguments: [--debug]

Plugins:
+ OpeningHoursEditor (34867)
+ apache-commons (34506)
+ buildings_tools (34867)
+ continuosDownload (82)
+ download_along (34869)
+ ejml (34389)
+ geotools (34513)
+ jaxb (34678)
+ jts (34524)
+ o5m (34867)
+ opendata (34867)
+ pbf (34867)
+ poly (34867)
+ reltoolbox (34867)
+ reverter (34867)
+ undelete (34877)
+ utilsplugin2 (34867)

Last errors/warnings:
- W: No configuration settings found.  Using hardcoded default values for all pools.

[GerdP]

The patch implements a new method HistoryLoadTask.setChangesetDataNeeded(boolean b) which might be called with false to suppress the
unwanted calls. It is not yet called anywhere. Maybe it would be better to set it to false by default and use true in the HistoryBrowser which needs the data.

[GerdP]

add call to use new method

[GerdP]

In 14763/josm:

fix #17279: improve performance when retrieving history

[GerdP]

see also [o34881:34882]