Add metric for the actually used memory for global handles

Adds a metric for how much memory is actually used by live global
handles. This CL also fixes emitting of V8.Main.GlobalHandles. It was
using MetricSize::kSmall which added "Small." to the metric name.

Change-Id: I4a85e5b49a18e7b432a343eeff9aa926fc324645
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2659035
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#851102}

chrome/browser/metrics/process_memory_metrics_emitter.cc

@@ -309,9 +309,12 @@ const Metric kAllocatorDumpNamesForMetrics[] = {
     {"v8/main", "V8.Main.AllocatedObjects", MetricSize::kLarge,
      kAllocatedObjectsSize, EmitTo::kSizeInUkmAndUma,
      &Memory_Experimental::SetV8_Main_AllocatedObjects},
-    {"v8/main/global_handles", "V8.Main.GlobalHandles", MetricSize::kSmall,
+    {"v8/main/global_handles", "V8.Main.GlobalHandles", MetricSize::kLarge,
      kEffectiveSize, EmitTo::kSizeInUkmAndUma,
      &Memory_Experimental::SetV8_Main_GlobalHandles},
+    {"v8/main/global_handles", "V8.Main.GlobalHandles.AllocatedObjects",
+     MetricSize::kLarge, kAllocatedObjectsSize, EmitTo::kSizeInUkmAndUma,
+     &Memory_Experimental::SetV8_Main_GlobalHandles_AllocatedObjects},
     {"v8/main/heap", "V8.Main.Heap", MetricSize::kLarge, kEffectiveSize,
      EmitTo::kSizeInUkmAndUma, &Memory_Experimental::SetV8_Main_Heap},
     {"v8/main/heap", "V8.Main.Heap.AllocatedObjects", MetricSize::kLarge,

chrome/browser/metrics/process_memory_metrics_emitter_unittest.cc

@@ -214,6 +214,10 @@ void PopulateRendererMetrics(GlobalMemoryDumpPtr& global_dump,
   SetAllocatorDumpMetric(
       pmd, "v8/main/global_handles", "effective_size",
       metrics_mb_or_count["V8.Main.GlobalHandles"] * 1024 * 1024);
+  SetAllocatorDumpMetric(
+      pmd, "v8/main/global_handles", "allocated_objects_size",
+      metrics_mb_or_count["V8.Main.GlobalHandles.AllocatedObjects"] * 1024 *
+          1024);
 
   SetAllocatorDumpMetric(pmd, "v8/main/heap", "effective_size",
                          metrics_mb_or_count["V8.Main.Heap"] * 1024 * 1024);
@@ -357,8 +361,9 @@ MetricMap GetExpectedRendererMetrics() {
         {"PartitionAlloc", 140}, {"BlinkGC", 150}, {"V8", 160},
         {"V8.AllocatedObjects", 70}, {"V8.Main", 100},
         {"V8.Main.AllocatedObjects", 30}, {"V8.Main.Heap", 98},
-        {"V8.Main.GlobalHandles", 3}, {"V8.Main.Heap.AllocatedObjects", 28},
+        {"V8.Main.GlobalHandles", 3},
-        {"V8.Main.Heap.CodeSpace", 11},
+        {"V8.Main.GlobalHandles.AllocatedObjects", 2},
+        {"V8.Main.Heap.AllocatedObjects", 28}, {"V8.Main.Heap.CodeSpace", 11},
         {"V8.Main.Heap.CodeSpace.AllocatedObjects", 1},
         {"V8.Main.Heap.LargeObjectSpace", 12},
         {"V8.Main.Heap.LargeObjectSpace.AllocatedObjects", 2},

gin/v8_isolate_memory_dump_provider.cc

@@ -264,6 +264,14 @@ void V8IsolateMemoryDumpProvider::DumpHeapStatistics(
       base::trace_event::MemoryAllocatorDump::kNameSize,
       base::trace_event::MemoryAllocatorDump::kUnitsBytes,
       heap_statistics.total_global_handles_size());
+  global_handles_dump->AddScalar(
+      "allocated_objects_size",
+      base::trace_event::MemoryAllocatorDump::kUnitsBytes,
+      heap_statistics.used_global_handles_size());
+  if (system_allocator_name) {
+    process_memory_dump->AddSuballocation(global_handles_dump->guid(),
+                                          system_allocator_name);
+  }
 
   // Dump object statistics only for detailed dumps.
   if (args.level_of_detail !=

tools/metrics/histograms/histograms_xml/histogram_suffixes_list.xml

@@ -14760,7 +14760,9 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   <suffix name="V8.AllocatedObjects"
       label="Only counting objects allocated by V8 javascript engine."/>
   <suffix name="V8.Main.GlobalHandles"
-      label="Memory used by V8 global handles in the main isolate."/>
+      label="Total memory used by V8 global handles in the main isolate."/>
+  <suffix name="V8.Main.GlobalHandles.AllocatedObjects"
+      label="Allocated memory used by V8 global handles in the main isolate."/>
   <suffix name="V8.Main.Heap" label="Only counting memory used by V8 heap"/>
   <suffix name="V8.Main.Heap.AllocatedObjects"
       label="Only counting objects allocated in V8 heap"/>

tools/metrics/ukm/ukm.xml

@@ -8959,6 +8959,11 @@ be describing additional metrics about the same event.
       Measure of memory consumed by global handles in V8.
     </summary>
   </metric>
+  <metric name="V8.Main.GlobalHandles.AllocatedObjects">
+    <summary>
+      Measure of memory consumed by used global handles in V8.
+    </summary>
+  </metric>
   <metric name="V8.Main.Heap">
     <summary>
       Measure of memory consumed by the main heap of V8.