The Firefox profiler output needs to generate a subcategory column for the frameTable

[mstange]

It currently sets frameTable.subcategory to null, see here:

vernier/lib/vernier/output/firefox.rb

Lines 487 to 509 in c4e1980

	def frame_table
	funcs = @stack_table_hash[:frame_table].fetch(:func)
	lines = @stack_table_hash[:frame_table].fetch(:line)
	size = funcs.length
	none = [nil] * size
	categories = @frame_categories.map(&:idx)
	raise unless lines.size == funcs.size
	{
	address: [-1] * size,
	inlineDepth: [0] * size,
	category: categories,
	subcategory: nil,
	func: funcs,
	nativeSymbol: none,
	innerWindowID: none,
	implementation: @frame_implementations,
	line: lines,
	column: none,
	length: size
	}
	end

This does not conform to the type definitions in the Firefox profiler types, see firefox-devtools/profiler#5368 .

[mstange]

The relevant line of code was probably meant to say none instead of nil.

[joshuay03]

@mstange Thank you! Addressing in #129. Also thanks for adding back support for existing profiles in firefox-devtools/profiler#5369.