Enable FractionalScrollOffsets

This enables fractional scroll offsets which allows non-integer values
in Blink's scrolling data structures.

https://github.com/bokand/RenderingIndependentScrollOffsets/blob/master/README.md

Bug: 414283
Change-Id: I145899dd4a3ae9f3b3c936749fbe0b52cbc9ba3e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1766355
Auto-Submit: David Bokan <bokan@chromium.org>
Commit-Queue: Nasko Oskov <nasko@chromium.org>
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Reviewed-by: Nasko Oskov <nasko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#690942}

content/public/common/content_features.cc

@@ -150,7 +150,7 @@ const base::Feature kFontSrcLocalMatching{"FontSrcLocalMatching",
 // Enables scrollers inside Blink to store scroll offsets in fractional
 // floating-point numbers rather than truncating to integers.
 const base::Feature kFractionalScrollOffsets{"FractionalScrollOffsets",
-                                             base::FEATURE_DISABLED_BY_DEFAULT};
+                                             base::FEATURE_ENABLED_BY_DEFAULT};
 
 // Puts network quality estimate related Web APIs in the holdback mode. When the
 // holdback is enabled the related Web APIs return network quality estimate

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -705,7 +705,7 @@
     },
     {
       name: "FractionalScrollOffsets",
-      status: "experimental",
+      status: "stable",
     },
     {
       name: "FreezeFramesOnVisibility",