ANGLE shader compilation error

[SamRodri]

Both the current crates.io 0.68 release and upstream branch fail when running with ANGLE.

// shader name: brush_blend

C:\\fakepath(455,1-7): error X3004: undeclared identifier '_result'

Warning: D3D shader compilation failed with default flags. (ps_5_0)
 Retrying with skip validation
C:\\fakepath(455,1-7): error X3004: undeclared identifier '_result'

Warning: D3D shader compilation failed with skip validation flags. (ps_5_0)
 Retrying with skip optimization
C:\\fakepath(455,1-7): error X3004: undeclared identifier '_result'

Warning: D3D shader compilation failed with skip optimization flags. (ps_5_0)


Failed to create D3D shaders.

This a known issue #3661 that has reoccurred, a workaround is documented in the driver issues wiki.

I have patches ready targeting both upstream and 0.68, if you guys want a pull request just tell me what branch to target, otherwise feel free to copy upstream (Bugzilla?)

[mrobinson]

@SamRodri These kind of changes to upstream functionality aren't typically the ones we apply downstream. Would you be willing to submit this directly to Gecko? Thanks.