Add PRESUBMIT check if modified UMA histogram name can be found (2)

Add PRESUBMIT check if modified UMA histogram name can be found (2)

This CL is an iteration of http://crrev.com/766713004, that got reverted
after http://crbug.com/445265 because it could not cope correctly
with structures of the type:

<histogram_suffixes name="SafeBrowsingStores.SBWhiteLists" separator=".">
  <suffix name="CSD" label="CSD"/>
  <suffix name="DownloadWhitelist" label="DownloadWhitelist"/>
  <affected-histogram name="SB2.DatabaseKilobytes"/>
</histogram_suffixes>

(in particular: affected-histogram-suffixes).

Limitation that should be solved now.

Original description ---------------------------------------------------

Add PRESUBMIT check if modified UMA histogram name can be found

This Presubmit checks if some diffs affect any UMA_HISTOGRAM_*
macro and, if so, checks if the histogram name is to be found
in either tools/metrics/histograms/histograms.xml or in the
CL diffs.

Addresses the problem of someone modifying code and
inadvertently forgetting a corresponding histograms.xml
adaptation, that has happened in the past.

BUG=434420, 445265

Review URL: https://codereview.chromium.org/885783007

Cr-Commit-Position: refs/heads/master@{#314557}