Adding malloc allocator metric for objects allocated through shim

base/trace_event/malloc_dump_provider.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/trace_event/malloc_dump_provider.h"
 
 #include <stddef.h>
 
 #include <unordered_map>
 
@@ skipping 276 matching lines @@
   if (!heap_profiler_enabled_)
     return true;
 
   // The dumps of the heap profiler should be created only when heap profiling
   // was enabled (--enable-heap-profiling) AND a DETAILED dump is requested.
   // However, when enabled, the overhead of the heap profiler should be always
   // reported to avoid oscillations of the malloc total in LIGHT dumps.
 
   tid_dumping_heap_ = PlatformThread::CurrentId();
   // At this point the Insert/RemoveAllocation hooks will ignore this thread.
-  // Enclosing all the temporariy data structures in a scope, so that the heap
-  // profiler does not see unabalanced malloc/free calls from these containers.
+  // Enclosing all the temporary data structures in a scope, so that the heap
+  // profiler does not see unbalanced malloc/free calls from these containers.
   {
+    size_t shim_allocated_objects_size = 0;
+    size_t shim_allocated_objects_count = 0;
     TraceEventMemoryOverhead overhead;
     std::unordered_map<AllocationContext, AllocationMetrics> metrics_by_context;
     {
       AutoLock lock(allocation_register_lock_);
       if (allocation_register_) {
         if (args.level_of_detail == MemoryDumpLevelOfDetail::DETAILED) {
           for (const auto& alloc_size : *allocation_register_) {
             AllocationMetrics& metrics = metrics_by_context[alloc_size.context];
             metrics.size += alloc_size.size;
             metrics.count++;
+
+            // Aggregate data for objects allocated through the shim.
+            shim_allocated_objects_size += alloc_size.size;
+            shim_allocated_objects_count++;
           }
         }
         allocation_register_->EstimateTraceMemoryOverhead(&overhead);
       }
+
+      inner_dump->AddScalar("shim_allocated_objects_size",
+                             MemoryAllocatorDump::kUnitsBytes,
+                             shim_allocated_objects_size);
+      inner_dump->AddScalar("shim_allocator_object_count",
+                             MemoryAllocatorDump::kUnitsObjects,
+                             shim_allocated_objects_count);
     }  // lock(allocation_register_lock_)
     pmd->DumpHeapUsage(metrics_by_context, overhead, "malloc");
   }
   tid_dumping_heap_ = kInvalidThreadId;
 
   return true;
 }
 
 void MallocDumpProvider::OnHeapProfilingEnabled(bool enabled) {
 #if BUILDFLAG(USE_EXPERIMENTAL_ALLOCATOR_SHIM)
@@ skipping 47 matching lines @@
       tid_dumping_heap_ == PlatformThread::CurrentId())
     return;
   AutoLock lock(allocation_register_lock_);
   if (!allocation_register_)
     return;
   allocation_register_->Remove(address);
 }
 
 }  // namespace trace_event
 }  // namespace base