Revert "[tools/perf] Add webview_cpu_usage metric"

This reverts commit 5c76e821.

Reason for revert: Caused consistent failure on the following bot:
https://ci.chromium.org/p/chromium/builders/ci/Win%207%20Tests%20x64%20%281%29/67399

Original change's description:
> [tools/perf] Add webview_cpu_usage metric
> 
> This change adds a metric that calculates the amount of time WebView
> spends on different frequencies.
> 
> Bug: b/157855323
> Change-Id: Ibb1fa61cc2ba1479f2b76ef642dc03c64a9a14b5
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2231452
> Reviewed-by: Mikhail Khokhlov <khokhlov@google.com>
> Commit-Queue: Oksana Zhuravlova <oksamyt@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#775713}

TBR=oksamyt@chromium.org,khokhlov@google.com

Change-Id: I58544fcad9e209ee005a4b6e5981ef780ab4b6d2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: b/157855323
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2233681Reviewed-by: Yi Gu <yigu@chromium.org>
Commit-Queue: Yi Gu <yigu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#775753}

tools/perf/core/tbmv3/metrics/webview_cpu_usage_metric.proto

-syntax = "proto2";
-
-package perfetto.protos;
-
-import "protos/perfetto/metrics/metrics.proto";
-import "protos/perfetto/metrics/custom_options.proto";
-
-message WebViewCPUUsageMetric {
-  optional int64 cpu_time_nanos_below_1ghz = 1;
-  optional int64 cpu_time_nanos_above_1ghz = 2;
-};
-
-extend TraceMetrics {
-  optional WebViewCPUUsageMetric webview_cpu_usage_metric = 458;
-}

tools/perf/core/tbmv3/metrics/webview_cpu_usage_metric.sql

--- WebView is embedded in the hosting app's main process, which means it shares some threads
--- with the host app's work. In the future, we will approximate WebView-related power usage
--- by selecting user slices that belong to WebView and estimating their power use
--- through the CPU time they consume at different core frequencies.
--- The initial version of this metric calculates the total time (in nanoseconds)
--- WebView slices spend in different frequency ranges.
-
-SELECT RUN_METRIC('android/android_cpu.sql');
-
-DROP VIEW IF EXISTS webview_slice;
-
-CREATE VIEW webview_slice AS
-  SELECT *
-  FROM
-    -- TODO(b/156788923): add better conditions.
-    slice WHERE category = 'android_webview';
-
-DROP VIEW IF EXISTS top_level_webview_slice;
-
--- Since we filter out some slices in webview_slice above, we cannot use the "depth" column
--- to select only the top-level webview slices. Instead, we have to join webview_slice with itself,
--- selecting only those events that do not have any children in webview_slice.
-CREATE VIEW top_level_webview_slice AS
-  SELECT *
-  FROM
-    webview_slice s1 WHERE
-  (SELECT COUNT(1)
-  FROM (
-    SELECT *
-    FROM
-      webview_slice s2
-    WHERE s1.track_id = s2.track_id
-    AND s2.ts < s1.ts
-    AND s2.ts + s2.dur > s1.ts + s1.dur
-    LIMIT 1)
-   ) == 0;
-
-DROP VIEW IF EXISTS slices_threads;
-
-CREATE VIEW slices_threads AS
-  SELECT
-    top_level_webview_slice.ts,
-    top_level_webview_slice.dur,
-    thread_track.utid
-FROM top_level_webview_slice INNER JOIN thread_track
-  ON top_level_webview_slice.track_id = thread_track.id;
-
-DROP TABLE IF EXISTS slices_freq;
-
-CREATE VIRTUAL TABLE slices_freq
-  USING SPAN_JOIN (cpu_freq_sched_per_thread PARTITIONED utid,
-                   slices_threads PARTITIONED utid);
-
--- Get frequencies by utid and cpu.
-SELECT RUN_METRIC('android/android_cpu_raw_metrics_per_core.sql',
-  'input_table', 'slices_freq',
-  'output_table', 'webview_raw_metrics_per_core');
-
--- TODO(b/155980166): use another query to estimate power consumption based on frequencies.
-
-CREATE VIEW webview_cpu_usage_metric_output AS
-SELECT WebViewCPUUsageMetric(
-    'cpu_time_nanos_below_1ghz',
-    (SELECT IFNULL(CAST(SUM(runtime_ns) AS INT), 0)
-    FROM
-      webview_raw_metrics_per_core
-    WHERE avg_freq_khz < 1000000),
-    'cpu_time_nanos_above_1ghz',
-    (SELECT IFNULL(CAST(SUM(runtime_ns) AS INT), 0)
-    FROM
-      webview_raw_metrics_per_core
-    WHERE avg_freq_khz >= 1000000)
-);