Register V8 garbage collection reason histograms in histograms.xml

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 04b570582d5817f1ad9fa0903ff7a145d653ed92..24e8c059916598203bfd32d2d8f5624971ba69a9 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -64284,6 +64284,11 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <summary>Time spent in finalizing incremental marking.</summary>
 </histogram>
 
+<histogram name="V8.GCIncrementalMarkingReason" units="GarbageCollectionReason">
+  <owner>ulan@chromium.org</owner>
+  <summary>Reason an incremental marking was started in V8.</summary>
+</histogram>
+
 <histogram name="V8.GCIncrementalMarkingStart" units="ms">
   <owner>jochen@chromium.org</owner>
   <owner>hpayer@chromium.org</owner>
@@ -64296,12 +64301,22 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <summary>Time spent in LowMemoryNotifications.</summary>
 </histogram>
 
+<histogram name="V8.GCMarkCompactReason" units="GarbageCollectionReason">
+  <owner>ulan@chromium.org</owner>
+  <summary>Reason a mark-compact garbage collection was started in V8.</summary>
+</histogram>
+
 <histogram name="V8.GCScavenger" units="ms">
   <owner>jochen@chromium.org</owner>
   <owner>hpayer@chromium.org</owner>
   <summary>Time spent in scavenging phase of GC.</summary>
 </histogram>
 
+<histogram name="V8.GCScavengeReason" units="GarbageCollectionReason">
+  <owner>ulan@chromium.org</owner>
+  <summary>Reason a scavenge garbage collection was started in V8.</summary>
+</histogram>
+
 <histogram name="V8.Initializer.LoadV8Snapshot.Result"
     enum="V8InitializerLoadV8SnapshotResult">
   <owner>oth@chromium.org</owner>
@@ -81489,6 +81504,31 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="10" label="GammaNamed"/>
 </enum>
 
+<enum name="GarbageCollectionReason" type="int">
+  <int value="0" label="kUnknown"/>
+  <int value="1" label="kAllocationFailure"/>
+  <int value="2" label="kAllocationLimit"/>
+  <int value="3" label="kContextDisposal"/>
+  <int value="4" label="kCountersExtension"/>
+  <int value="5" label="kDebugger"/>
+  <int value="6" label="kDeserializer"/>
+  <int value="7" label="kExternalMemoryPressure"/>
+  <int value="8" label="kFinalizeMarkingViaStackGuard"/>
+  <int value="9" label="kFinalizeMarkingViaTask"/>
+  <int value="10" label="kFullHashtable"/>
+  <int value="11" label="kHeapProfiler"/>
+  <int value="12" label="kIdleTask"/>
+  <int value="13" label="kLastResort"/>
+  <int value="14" label="kLowMemoryNotification"/>
+  <int value="15" label="kMakeHeapIterable"/>
+  <int value="16" label="kMemoryPressure"/>
+  <int value="17" label="kMemoryReducer"/>
+  <int value="18" label="kRuntime"/>
+  <int value="19" label="kSamplingProfiler"/>
+  <int value="20" label="kSnapshotCreator"/>
+  <int value="21" label="kTesting"/>
+</enum>
+
 <enum name="GATTCharacteristicHash" type="int">
 <!-- Hash values can be produced using tool: bluetooth_metrics_hash (Only built via GN, not GYP) -->