memory-infra: Remove is_enabled_ from MDM

base/trace_event/process_memory_dump.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/process_memory_dump.h"
 
 #include <errno.h>
 
 #include <vector>
 
@@ skipping 235 matching lines @@
   return GetAllocatorDump(GetSharedGlobalAllocatorDumpName(guid));
 }
 
 void ProcessMemoryDump::DumpHeapUsage(
     const std::unordered_map<base::trace_event::AllocationContext,
                              base::trace_event::AllocationMetrics>&
         metrics_by_context,
     base::trace_event::TraceEventMemoryOverhead& overhead,
     const char* allocator_name) {
   if (!metrics_by_context.empty()) {
+    // We shouldn't end up here unless we're doing a detailed dump with
+    // heap profiling enabled and if that is the case tracing should be
+    // enabled which sets up the heap profiler serialization state.
+    if (!heap_profiler_serialization_state()) {
+      NOTREACHED();
+      return;
+    }
     DCHECK_EQ(0ul, heap_dumps_.count(allocator_name));
     std::unique_ptr<TracedValue> heap_dump = ExportHeapDump(
         metrics_by_context, *heap_profiler_serialization_state());
     heap_dumps_[allocator_name] = std::move(heap_dump);
   }
 
   std::string base_name = base::StringPrintf("tracing/heap_profiler_%s",
                                              allocator_name);
   overhead.DumpInto(base_name.c_str(), this);
 }
@@ skipping 101 matching lines @@
 
 MemoryAllocatorDump* ProcessMemoryDump::GetBlackHoleMad() {
   DCHECK(is_black_hole_non_fatal_for_testing_);
   if (!black_hole_mad_)
     black_hole_mad_.reset(new MemoryAllocatorDump("discarded", this));
   return black_hole_mad_.get();
 }
 
 }  // namespace trace_event
 }  // namespace base