Roll Skia from 4f6568ba7051 to df78435c2f26 (4 revisions) (flutter#52959)

https://skia.googlesource.com/skia.git/+log/4f6568ba7051..df78435c2f26

2024-05-21 michaelludwig@google.com Update minimum version of Mac and iOS build tasks
2024-05-21 michaelludwig@google.com [graphite] Set DrawAtlas label on atlas page proxy
2024-05-21 drott@chromium.org Reland "[Fontations-backend] Hook up Skrifa hinting support"
2024-05-21 michaelludwig@google.com [graphite] Use approx-fit textures in GenerateMipmaps and RescaleImage

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/skia-flutter-autoroll
Please CC brianosman@google.com,jlavrova@google.com,jonahwilliams@google.com,rmistry@google.com on the revert to ensure that a human
is aware of the problem.

To file a bug in Skia: https://bugs.chromium.org/p/skia/issues/entry
To file a bug in Flutter: https://github.com/flutter/flutter/issues/new/choose

To report a problem with the AutoRoller itself, please file a bug:
https://issues.skia.org/issues/new?component=1389291&template=1850622

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

Author: skia-flutter-autoroll

DEPS

@@ -14,7 +14,7 @@ vars = {
   'flutter_git': 'https://flutter.googlesource.com',
   'skia_git': 'https://skia.googlesource.com',
   'llvm_git': 'https://llvm.googlesource.com',
-  'skia_revision': '4f6568ba7051c6f125c148a4c8a6d29e3d48c5e7',
+  'skia_revision': 'df78435c2f264ba0987d19e7b46fac27c5c711ca',
 
   # WARNING: DO NOT EDIT canvaskit_cipd_instance MANUALLY
   # See `lib/web_ui/README.md` for how to roll CanvasKit to a new version.

ci/licenses_golden/licenses_skia

@@ -1,4 +1,4 @@
-Signature: a71d57003e1526bb56dd70a1d8409da7
+Signature: 53f935f34a0892c3c836aad2d9ea56ce
 
 ====================================================================================================
 LIBRARY: etc1