Bugzilla

The main goal is to simplify the logic in setURI, and create a more easier to understand flow of operations.

It involves making Persisted Search more contained, offload some responsibilities to UrlbarSearchTermsPersistence, and store fewer state variables than the patch that was first reviewed. I also simplified code in UrlbarSearchTermsPersistence.

**How Search Terms Persist:**

**Step 1**

When the page first appears, set state for search terms persistence. First load doesn't necessarily mean no tab switch or same page load, as a user could load a browser in the background tab. In that latter case, the first "view" may occur on a tab switch and the state won't exist because `setURI` will never have been called with that browser object being selected.

Once the state has been set, the only property that could be updated is `shouldPersist`. Otherwise, don't update the state object unless a full new page load occurs.

**Step 2**

Call `shouldPersist`. This has all the logic for when search terms should persist and gets called anytime `setURI` is called.

The conditions in which we shouldn't persist:

- There's no reason to show search terms:
  - The persist state is missing.
  - There are no search terms extracted from the URL.
- We need to temporarily hide the search terms, such as by handleRevert
  - `hideSearchTerms` is provided to setURI
- There is an user typed value and it differs from the search terms
- A single page application moved to a secondary page
- After the initial page load, there's the search mode (or lack of search mode) differs from the persist engine.

**Step 3**

Determine if we need to update `this.window.gBrowser.userTypedValue`. If we're going to persist, set `userTypedValue` to the search terms, which will keep the search mode and non-search mode state consistent. This'll also enable the ability to reuse existing logic that determines how to set `value`.

On same page loads, when switching from persist to non-persist, and search term equals the userTypedValue, then `null` the userTypedValue so that the URL shows.

**Step 4**

In the area of setURI which has logic for search mode, if we persist, ensure the search mode (or lack of search mode) is consistent with the engine. If it is, do nothing. If it isn't, either nullify the search mode or enter search mode.

Erroneous patch.