Split the aggregate dictionary that contains content settings exceptions for all content types into separate dictionary holding one content type each.
Old dictionary entry example:
"www.google.com,*": {"cookies": <value>, "plugins": <value>, last_used: {"cookies": <timestamp>, "plugins": <timestamp>}, "per_plugin": {<resource_id>: <value>}}
Split into separate dictionaries:
cookies:
"www.google.com,*": {"setting": <value>, "last_used": <timestamp>}
plugins:
"www.google.com,*": {"setting": <value>, "last_used": <timestamp>, "per_resource": {<resource_id>: <value>}}
For migration between versions of Chrome, we use a similar logic as when we migrated the default preferences in https://codereview.chromium.org/1004733003/ .
1. On the first run, migrate all settings (PrefProvider::MigrateAllExceptions()).
2. Whenever the old dictionary preference changes, propagate the syncable entries into the new preferences (PrefProvider::OnOldContentSettingsPatternPairsChanged()).
3. Whenever one of the new preferences changes, and it is syncable, we write it back to the old dictionary preference as well (ContentSettingsPref::OnPrefChanged()).
Note that PrefProvider manages its old dictionary preference the same way as ContentSettingsPref does a new preference, and ContentSettingsPref needs access to the old preference as well, which leads to some duplication in the code (UpdateOldPref() is just a modified version of UpdatePref(); both use some of the same constructs). We use the convention of referring to attributes and methods managing the old dictionary preference as "old" in the name.
BUG=452388
Review URL: https://codereview.chromium.org/1005303003
Cr-Commit-Position: refs/heads/master@{#323585}
10 files changed
