[GStreamer] Load Flite when speech synthesis is first used instead of linking it - #77409

243c31d

[GStreamer] Load Flite when speech synthesis is first used instead of linking it
https://bugs.webkit.org/show_bug.cgi?id=327957

Reviewed by NOBODY (OOPS!).

Linking Flite put its 13 libraries in every WebKit process. One voice that
WebKit doesn't even use, cmu_time_awb, has over 31,000 symbol relocations
against itself, about half of all the symbol bindings the dynamic linker
does when a WebKit process starts. Each of those lookups searches the global
scope of 168 libraries.

Load the Flite libraries and the four voices WebKit uses with dlopen() the
first time speech synthesis needs them, and call Flite through the resolved
functions. Without Flite at runtime, speech synthesis now offers no voices
instead of crashing.

A bare WPEWebProcess goes from 34 ms to 22 ms from exec to exit, and from
168 to 154 libraries.

* Source/WebCore/platform/GStreamer.cmake:
* Source/WebCore/platform/gstreamer/GUniquePtrFlite.h:
* Source/WebCore/platform/gstreamer/WebKitFliteSourceGStreamer.cpp:
(fliteSymbol):
(fliteLibrary):
(WebCore::fliteDeleteVoice):
(WebCore::fliteDeleteWave):
(webkitFliteSrcCreate):
(fliteVoices):
(ensureFliteVoicesInitialized):
(webKitFliteSrcSetUtterance):
(WTF::toArray): Deleted.

243c31d