[trace processor] Add WebView CPU usage metric

This change adds a set of queries that creates a table with WebView
slices CPU time usage. This file will be used to produce metrics in
different formats.

Bug: 158665113
Change-Id: I17ccb3e0c2848dea0263ffbd55bb98504052a8ca
diff --git a/Android.bp b/Android.bp
index b1fdcd5..eda6cbf 100644
--- a/Android.bp
+++ b/Android.bp
@@ -55,6 +55,7 @@
     "src/trace_processor/metrics/android/unsymbolized_frames.sql",
     "src/trace_processor/metrics/chrome/chrome_processes.sql",
     "src/trace_processor/metrics/trace_metadata.sql",
+    "src/trace_processor/metrics/webview/webview_cpu_usage.sql",
   ],
   cmd: "$(location tools/gen_merged_sql_metrics.py) --cpp_out=$(out) $(in)",
   out: [