[tracing] Expose a GetOrCreateAllocatorDump for memory tracing

Small non-functional refactor in preparation of upcoming CLs.

BUG=
TBR=reed@google.com

Review URL: https://codereview.chromium.org/1387833004

Cr-Commit-Position: refs/heads/master@{#352453}

2 files changed, 11 insertions, 0 deletions

diff --git a/base/trace_event/process_memory_dump.cc b/base/trace_event/process_memory_dump.cc
index 67118f1..df26ef5 100644
--- a/base/trace_event/process_memory_dump.cc
+++ b/base/trace_event/process_memory_dump.cc
@@ -56,6 +56,14 @@ MemoryAllocatorDump* ProcessMemoryDump::GetAllocatorDump(
   return it == allocator_dumps_.end() ? nullptr : it->second;
 }
 
+MemoryAllocatorDump* ProcessMemoryDump::GetOrCreateAllocatorDump(
+    const std::string& absolute_name) {
+  MemoryAllocatorDump* mad = GetAllocatorDump(absolute_name);
+  if (mad)
+    return mad;
+  return CreateAllocatorDump(absolute_name);
+}
+
 MemoryAllocatorDump* ProcessMemoryDump::CreateSharedGlobalAllocatorDump(
     const MemoryAllocatorDumpGuid& guid) {
   // A shared allocator dump can be shared within a process and the guid could
diff --git a/base/trace_event/process_memory_dump.h b/base/trace_event/process_memory_dump.h
index da18a14..7a16aa4 100644
--- a/base/trace_event/process_memory_dump.h
+++ b/base/trace_event/process_memory_dump.h
@@ -64,6 +64,9 @@ class BASE_EXPORT ProcessMemoryDump {
   // nullptr if not found.
   MemoryAllocatorDump* GetAllocatorDump(const std::string& absolute_name) const;
 
+  MemoryAllocatorDump* GetOrCreateAllocatorDump(
+      const std::string& absolute_name);
+
   // Creates a shared MemoryAllocatorDump, to express cross-process sharing.
   // Shared allocator dumps are allowed to have duplicate guids within the
   // global scope, in order to reference the same dump from multiple processes.