This change also adds TimeRecorder which records time at the start
of each frame to capture the latest vsync target display time and
wires it in to the rasterizer to add trace events when there is a lag.

The JSON codec is awkward to use in the wrapper (since the client has to build and link one of the JSON libraries to do so). Since it would be very cumbersome to wrap in a C API, and there's essentially no reason to use it instead of the standard codec, this removes it from the wrapper entirely.

Since some system channels (internal to the engine) still use it, it's moved into common/cpp instead of being eliminated entirely. Internally we always use RapidJSON though, so the jsoncpp implementation is removed. Also adds some unit test coverage, since there wasn't any.

Fixes #30669

* "Reland Clang 11, roll buildroot to 1bc40a5f916adb93d87e2a2230a0ec43db876c1c, take 4 (#17467)" (#17482)"

This reverts commit 8166a91b.

* format code

* Roll buildroot to 3a27de1c5bb0f50be7d3efe3e00de4f6068c9f30

There is no ability to compile shaders online and cache those binaries when
using the Metal backend. SkSL caching must always be used.

* Initialize locale from FlutterEngine

Revert "Reland Clang 11, roll buildroot to 1bc40a5f916adb93d87e2a2230a0ec43db876c1c, take 3 (#17467)" (#17482)

This reverts commit 39b77188.

* Reland Clang 11, Roll buildroot to 1bc40a5f916adb93d87e2a2230a0ec43db876c1c (#17457)" (#17464)

This reverts commit 9eacd028.

* Skip more image tests, use newer dsymutil, add missing symbols

Revert "Reland Clang 11, Roll buildroot to 1bc40a5f916adb93d87e2a2230a0ec43db876c1c (#17457)" (#17464)

This reverts commit a4026cc9.

* Reland "Roll Clang to v11, roll buildroot to fe13f79dce4ce9aab3209f11988d825dcf580b4a, allow newly exported symbols (#17440)" (#17451)"

This reverts commit a870bc53.

* skip golden that is different on macos

* buildroot to 1bc40a5f916adb93d87e2a2230a0ec43db876c1c

Started clearing out the semantics information in Dart as well as deleting the AccessibilityBridge. (#17433)

Revert "Roll Clang to v11, roll buildroot to fe13f79dce4ce9aab3209f11988d825dcf580b4a, allow newly exported symbols (#17440)" (#17451)

This reverts commit 8d723aeb.

Roll Clang to v11, roll buildroot to fe13f79dce4ce9aab3209f11988d825dcf580b4a, allow newly exported symbols (#17440)

* Buildroot to fe13f79dce4ce9aab3209f11988d825dcf580b4a

* whitelist more symbols

API staging is complete - these defines have been removed.