Add --ninja_weight_source option

It has 3 options for now.
* ninja_log: uses ninja log file for data source
* evenly_distributed: pass empty list for ninja to consider every work as the same
* not_used: do not use critical path logic in ninja

In addition, I added the option in the metrics to track

Bug: 271527305
Test: m --ninja_weight_source=ninja_log|empty|not_used
Change-Id: Ib4c812c20606a34b17d3f0edb71057b477c4f90e

ui/metrics/metrics_proto/metrics.proto

@@ -153,6 +153,11 @@ message BuildConfig {
 
   // Whether the user explicitly disabled bazel mixed builds for this build.
   optional bool force_disable_bazel_mixed_build = 7;
+
+  // NOT_USED - ninja doesn't use weight list.
+  // NINJA_LOG - ninja uses weight list based on previous builds by ninja log
+  // EVENLY_DISTRIBUTED - ninja thinks every task has the same weight.
+  optional NinjaWeightListSource ninja_weight_list_source = 8 [default = NOT_USED];
 }
 
 message SystemResourceInfo {
@@ -337,3 +342,9 @@ message JobInfo {
   // Description of a job
   optional string job_description = 2;
 }
+
+enum NinjaWeightListSource {
+  NOT_USED = 0;
+  NINJA_LOG = 1;
+  EVENLY_DISTRIBUTED = 2;
+}