Validation Agent Prompt Template

Use this prompt when launching the Phase 3 validation agent. Substitute the milestone numbers and paste your breaking change analysis table.

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I'm updating SkiaSharp's Skia submodule from m{CURRENT} to m{TARGET}. Here is the breaking change analysis I produced: [paste analysis table]

Please validate by (run from externals/skia):

1. Run: git diff upstream/chrome/m{CURRENT}..upstream/chrome/m{TARGET} --stat -- src/ include/ Count the files changed and compare to my analysis — did I miss any?
2. For each HIGH/MEDIUM item I identified, verify the C API impact by grepping src/c/ include/c/
3. Check for changes I may have filtered as "Graphite-only" that actually affect Ganesh:
   • Search shared GPU headers (include/gpu/GpuTypes.h, include/gpu/*.h outside ganesh/ and graphite/)
   • For each new type, grep include/gpu/ganesh/ to see if Ganesh consumes it
4. Check for removed/moved headers that our C API includes: grep -rh '#include' src/c/*.cpp | sort -u Then verify each included header still exists at upstream/chrome/m{TARGET}
5. Struct size audit: Check every static_assert(sizeof(...)) in src/c/sk_structs.cpp. For each asserted C++ struct, compare the target milestone's definition against our C API struct in include/c/sk_types.h. Flag any struct that gained or lost fields.
6. Deleted file audit: For each file deleted between milestones (git diff --diff-filter=D --name-only), check if our C API references it (#include or uses its types). For referenced deletions, search the target branch for where the content moved (git ls-tree -r upstream/chrome/m{TARGET} --name-only | grep STEM).
7. Removal verification: For any symbol claimed "removed" in the analysis, verify it is truly absent from the target branch (not just moved within the file): git show upstream/chrome/m{TARGET}:PATH | grep SYMBOL
8. Report: missed items, incorrect classifications, and confirmed items