Adding malloc allocator metric for objects allocated through shim

base/trace_event/malloc_dump_provider.cc

Index: base/trace_event/malloc_dump_provider.cc
diff --git a/base/trace_event/malloc_dump_provider.cc b/base/trace_event/malloc_dump_provider.cc
index 3a4017251abf94a6d5421e1c0a90dc715c14bf14..047f2c336d5c6295086316b12f883811ab9f2b0c 100644
--- a/base/trace_event/malloc_dump_provider.cc
+++ b/base/trace_event/malloc_dump_provider.cc
@@ -294,9 +294,11 @@ bool MallocDumpProvider::OnMemoryDump(const MemoryDumpArgs& args,
 
   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;
     {
@@ -307,10 +309,21 @@ bool MallocDumpProvider::OnMemoryDump(const MemoryDumpArgs& args,
             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");
   }