Fix trace processor diff tests

This broke in crrev.com/c/6617381. The CL removed a histogram from
production code, as well as the expectations of
test_chrome_histograms(). However, that test uses as input a fixed trace
file [1] that predates the histogram removal. Thus, the histogram should
remain in the expectation list.

[1] https://source.chromium.org/chromium/chromium/src/+/main:base/tracing/test/trace_processor/diff_tests/chrome/tests.py;l=76;drc=e151307bd462973e648fa8877293bc383cbc469e

Change-Id: Id13cdf12b9f972a905bde4d6c7cf83279ff00929
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6624434
Reviewed-by: Petr Cermak <petrcermak@chromium.org>
Commit-Queue: Petr Cermak <petrcermak@chromium.org>
Auto-Submit: Victor Vianna <victorvianna@google.com>
Cr-Commit-Position: refs/heads/main@{#1470412}


CrOS-Libchrome-Original-Commit: da3d63b1ee035b2fe88fea7885c6a60618b267c9
1 file changed