[tracing] Prevent memory maps dump for light dump requests

base/trace_event/process_memory_maps_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/process_memory_maps_dump_provider.h"
 
 #include <cctype>
 #include <fstream>
 
 #include "base/logging.h"
@@ skipping 149 matching lines @@
 ProcessMemoryMapsDumpProvider::ProcessMemoryMapsDumpProvider() {
 }
 
 ProcessMemoryMapsDumpProvider::~ProcessMemoryMapsDumpProvider() {
 }
 
 // Called at trace dump point time. Creates a snapshot of the memory maps for
 // the current process.
 bool ProcessMemoryMapsDumpProvider::OnMemoryDump(const MemoryDumpArgs& args,
                                                  ProcessMemoryDump* pmd) {
-  // TODO(ssid): Use MemoryDumpArgs to create light dumps when requested
-  // (crbug.com/499731).
+  // Snapshot of memory maps is not taken for light dump requests.
+  if (args.level_of_detail == MemoryDumpArgs::LEVEL_OF_DETAIL_LOW)
+    return true;
 
   uint32 res = 0;
 
 #if defined(OS_LINUX) || defined(OS_ANDROID)
   if (UNLIKELY(proc_smaps_for_testing)) {
     res = ReadLinuxProcSmapsFile(proc_smaps_for_testing, pmd->process_mmaps());
   } else {
     std::ifstream proc_self_smaps("/proc/self/smaps");
     res = ReadLinuxProcSmapsFile(&proc_self_smaps, pmd->process_mmaps());
   }
 #else
   LOG(ERROR) << "ProcessMemoryMaps dump provider is supported only on Linux";
 #endif
 
   if (res > 0) {
     pmd->set_has_process_mmaps();
     return true;
   }
 
   return false;
 }
 
 }  // namespace trace_event
 }  // namespace base