[WK2] Decoding in ArgumentCoder<Vector<T>> should reserve initial capacity, avoid shrink-to-fit

[zdobersek]

0c0b202

[WK2] Decoding in ArgumentCoder<Vector<T>> should reserve initial capacity, avoid shrink-to-fit
https://bugs.webkit.org/show_bug.cgi?id=249077

Reviewed by Kimmo Kinnunen.

When decoding a Vector of non-trivial elements, use the decoded size to
reserve initial capacity and then perform unchecked appends of each
decoded element. This replaces the incremental grow-as-you-go appending
and the final shrink-to-fit operation which possibly ends up moving over
all the elements into the newly-allocated smaller buffer.

The decoding-moves-counter test is updated, with the only remaining and
unavoidable move of each element contained in the Vector happening when
that element is moved into the resulting Vector.

* Source/WebKit/Platform/IPC/ArgumentCoders.h:
* Tools/TestWebKitAPI/Tests/IPC/ArgumentCoderTests.cpp:
(TestWebKitAPI::TEST_F):

Canonical link: https://commits.webkit.org/257725@main

8fae0c3

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 🧪 win
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🛠 gtk	✅ 🛠 wincairo
✅ 🧪 webkitperl	🧪 ios-wk2	✅ 🧪 api-mac	💥 🧪 gtk-wk2
	🧪 api-ios	❌ 🧪 mac-wk1	⏳ 🧪 api-gtk
	✅ 🛠 tv	✅ 🧪 mac-wk2
	✅ 🛠 tv-sim	✅ 🧪 mac-AS-debug-wk2
✅ 🛠 🧪 merge	✅ 🛠 watch	✅ 🧪 mac-wk2-stress
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on current version of this PR (hash 8fae0c3)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 🧪 win
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🛠 gtk	✅ 🛠 wincairo
✅ 🧪 webkitperl	🧪 ios-wk2	✅ 🧪 api-mac	💥 🧪 gtk-wk2
	🧪 api-ios	❌ 🧪 mac-wk1	⏳ 🧪 api-gtk
	✅ 🛠 tv	✅ 🧪 mac-wk2
	✅ 🛠 tv-sim	✅ 🧪 mac-AS-debug-wk2
✅ 🛠 🧪 merge	✅ 🛠 watch	✅ 🧪 mac-wk2-stress
	✅ 🛠 watch-sim

[questgugou]

good project

[webkit-commit-queue]

Committed 257725@main (0c0b202): https://commits.webkit.org/257725@main

Reviewed commits have been landed. Closing PR #7444 and removing active labels.

[questgugou]

thankyou verymuch