1503481 - Cache visited URLs more efficiently in `GeckoViewHistory`

Status: NEW

(GeckoView :: General, enhancement, P5)

Description

[Lina Butler [:lina]]

GeckoViewHistory currently stores URI hash keys in `mTrackedLinks` (each of which holds an `nsIURI` pointer: https://searchfox.org/mozilla-central/rev/fc3d974254660b34638b2af9d5431618b191b233/netwerk/base/nsURIHashKey.h#63), and removes them once all links have been notified.

This means we need to query the delegate again and incur two IPC messages and two JNI calls every time we see a link that we already checked. Since we don't actually need the original URI, what if we stored just the hash in `mTrackedLinks` instead, and kept the entries around with `mStatus == TrackedURIStatus::Visited`?

Alternatively, or maybe in addition to the above, we could add LRU eviction for visited URIs. Both would let us cut down on memory use.

Bug 1197866 is related. `GlobalHistory` stores the visited set on the Java side, but I imagine the same would apply to C++.

Comment 1

[David Bolter [:davidb] (NeedInfo me for attention)]

Lina looks like you are taking this bug?

Comment 2

[Lina Butler [:lina]]

I think this is worth doing someday (and it's not quite a "good first bug"—but a good bug for a more experienced contributor), but not urgent. We can revisit if history lookups in our mobile apps turn out to be a bottleneck.

Comment 3

[Lina Butler [:lina]]

Bug 1594368, comment 1 suggests doing just that!

Comment 4

[Chris Peterson [:cpeterson]]

Enhancements should have severity N/A.