This breaks the Linux build with:
```
[ RUN ] PerformanceOverlayLayer.Gold
../../flutter/flow/layers/performance_overlay_layer_unittests.cc:70: Failure
Value of: golden_data != nullptr
Actual: false
Expected: true
Golden file not found: "/b/s/w/ir/k/src/flutter/testing/resources"/performance_overlay_gold.png.
Please either set --golden-dir, or make sure that the unit test is run from the right directory (e.g., flutter/engine/src).
```
This reverts commit 3f0ce769e2.
Reverting this broke the flow tests for the performance overlay:
```
../../flutter/flow/layers/performance_overlay_layer_unittests.cc:70: Failure
Value of: golden_data != nullptr
Actual: false
Expected: true
```
This reverts commit 8427d73c83.
* Revert "Revert "Add mock capability to PerformanceOverlayLayer (#7537)" (#7765)"
This reverts commit 693645e464.
* Add command line args for golden dir and font file
The shell was already designed to cleanly shut down the VM but it couldnt
earlier as |Dart_Initialize| could never be called after a |Dart_Cleanup|. This
meant that shutting down an engine instance could not shut down the VM to save
memory because newly created engines in the process after that point couldn't
restart the VM. There can only be one VM running in a process at a time.
This patch separate the previous DartVM object into one that references a
running instance of the DartVM and a set of immutable dependencies that
components can reference even as the VM is shutting down.
Unit tests have been added to assert that non-overlapping engine launches use
difference VM instances.
Behavior (visual) changes should be very minor. Things that are to be expected:
* A few things were not color managed correctly by the transform canvas (color emoji, some color filters). Those will be handled correctly with the tagged surfaces (although we're always transforming to sRGB, so nothing should change until we target a wider gamut).
* Image filtering will happen in the source color space, rather than the destination. Very minor.
* The transform canvas did caching of images in the destination color space. Now, the conversion happens at draw time. If there are performance issues, images can be pre-converted to the destination with makeColorSpace().
* Update GetCallbackHandle to use Dart_IsTearOff instead of a string
comparison to determine whether or not a closure was provided as an
argument to PluginUtilities.GetCallbackHandle.
Fixes#24394
As of the migration to Dart 2, it has been necessary to compile Dart to
kernel prior to execution. The embedder currently requires that the
resulting kernel file be named `kernel_blob.bin` and be located at the
root of the assets directory passed to the embedder API.
This patch updates the test_fixtures build rule to perform a kernel
compile using frontend_server, outputting `kernel_blob.bin` to
`fixtures/test_target_name` directory, and updates the embedder
unittests to specify the kernel file rather than the Dart source file.
Since the kernel compiler requires a `main()` function to be defined, it
also updates `simple_main.dart` from runtime_unittests to define
`main()` rather than `simple_main()`.
This also updates all existing sub-targets to be testonly.
This relands commit ac9e521a1d, which was
reverted in commit 4941125829. Rather than
running as prebuilt_dart_action, we use dart_action to ensure the
frontend snapshot it compatible with the VM on which it's executed.