Framegraph: add attachment information per subpass (#545)
Framegraph: add attachment information per subpass (#545)

This adds a lot of code, but it is mainly extracting information and
listing it in the framegraph node labels.

Bug: b/172588085
Test: manual, on several traces.
google/agi,google/agi,google/agi,google/agi,google/agi,google/agi,google/agi,google/agi