[histograms] Clean up histograms and add myself as owner

- Merge back_forward_cache into navigation folder.
- Move scheduling-related histograms from other to scheduler/.
- Add myself as owner for scheduler/ and navigation/.

R=sweilun@chromium.org,isherman@chromium.org

Change-Id: I6b4d296be8316d65fd6e7da1371f986fcf2fe706
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2503730Reviewed-by: Ilya Sherman <isherman@chromium.org>
Commit-Queue: Alexander Timin <altimin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821899}

components/metrics/generate_expired_histograms_array.gni

@@ -42,7 +42,6 @@ template("generate_expired_histograms_array") {
       "//tools/metrics/histograms/histograms_xml/auth/histograms.xml",
       "//tools/metrics/histograms/histograms_xml/auto/histograms.xml",
       "//tools/metrics/histograms/histograms_xml/autofill/histograms.xml",
-      "//tools/metrics/histograms/histograms_xml/back_forward_cache/histograms.xml",
       "//tools/metrics/histograms/histograms_xml/background/histograms.xml",
       "//tools/metrics/histograms/histograms_xml/blink/histograms.xml",
       "//tools/metrics/histograms/histograms_xml/bluetooth/histograms.xml",
@@ -77,8 +76,8 @@ template("generate_expired_histograms_array") {
       "//tools/metrics/histograms/histograms_xml/geolocation/histograms.xml",
       "//tools/metrics/histograms/histograms_xml/google/histograms.xml",
       "//tools/metrics/histograms/histograms_xml/gpu/histograms.xml",
-      "//tools/metrics/histograms/histograms_xml/histogram_suffixes_list.xml",
       "//tools/metrics/histograms/histograms_xml/hang_watcher/histograms.xml",
+      "//tools/metrics/histograms/histograms_xml/histogram_suffixes_list.xml",
       "//tools/metrics/histograms/histograms_xml/history/histograms.xml",
       "//tools/metrics/histograms/histograms_xml/holding_space/histograms.xml",
       "//tools/metrics/histograms/histograms_xml/image/histograms.xml",
@@ -121,6 +120,7 @@ template("generate_expired_histograms_array") {
       "//tools/metrics/histograms/histograms_xml/renderer4/histograms.xml",
       "//tools/metrics/histograms/histograms_xml/safe_browsing/histograms.xml",
       "//tools/metrics/histograms/histograms_xml/sb_client/histograms.xml",
+      "//tools/metrics/histograms/histograms_xml/scheduler/histograms.xml",
       "//tools/metrics/histograms/histograms_xml/search/histograms.xml",
       "//tools/metrics/histograms/histograms_xml/security/histograms.xml",
       "//tools/metrics/histograms/histograms_xml/service/histograms.xml",

tools/metrics/histograms/histograms_index.txt

@@ -8,7 +8,6 @@ tools/metrics/histograms/histograms_xml/assistant/histograms.xml
 tools/metrics/histograms/histograms_xml/auth/histograms.xml
 tools/metrics/histograms/histograms_xml/auto/histograms.xml
 tools/metrics/histograms/histograms_xml/autofill/histograms.xml
-tools/metrics/histograms/histograms_xml/back_forward_cache/histograms.xml
 tools/metrics/histograms/histograms_xml/background/histograms.xml
 tools/metrics/histograms/histograms_xml/blink/histograms.xml
 tools/metrics/histograms/histograms_xml/bluetooth/histograms.xml
@@ -87,6 +86,7 @@ tools/metrics/histograms/histograms_xml/renderer/histograms.xml
 tools/metrics/histograms/histograms_xml/renderer4/histograms.xml
 tools/metrics/histograms/histograms_xml/safe_browsing/histograms.xml
 tools/metrics/histograms/histograms_xml/sb_client/histograms.xml
+tools/metrics/histograms/histograms_xml/scheduler/histograms.xml
 tools/metrics/histograms/histograms_xml/search/histograms.xml
 tools/metrics/histograms/histograms_xml/security/histograms.xml
 tools/metrics/histograms/histograms_xml/service/histograms.xml
@@ -115,4 +115,4 @@ tools/metrics/histograms/histograms_xml/web_audio/histograms.xml
 tools/metrics/histograms/histograms_xml/web_core/histograms.xml
 tools/metrics/histograms/histograms_xml/web_rtc/histograms.xml
 tools/metrics/histograms/histograms_xml/weblayer/histograms.xml
-tools/metrics/histograms/histograms_xml/windows/histograms.xml
+tools/metrics/histograms/histograms_xml/windows/histograms.xml
\ No newline at end of file

tools/metrics/histograms/histograms_xml/navigation/OWNERS

@@ -4,4 +4,5 @@
 #  - You work in the same area as them.
 #  - They are already a good reviewer for the non-metrics part of the CL.
 # See tools/metrics/histograms/OWNERS for details.
+altimin@chromium.org
 tbansal@chromium.org

tools/metrics/histograms/histograms_xml/scheduler/OWNERS

+# If none of these reviewers are available, please send CLs to
+# <chromium-metrics-reviews@google.com>.
+# See tools/metrics/histograms/histograms_xml/OWNERS for details.
+altimin@chromium.org