Skip creating spdy_session_pool dump if pool is empty in MemoryDumpProvider

net/spdy/spdy_session_pool.cc

Index: net/spdy/spdy_session_pool.cc
diff --git a/net/spdy/spdy_session_pool.cc b/net/spdy/spdy_session_pool.cc
index bba426920241fbaf46374819dd866e15a8138bba..59cfeca5e17731eb59e9c00d432dbeb99f7cfeba 100644
--- a/net/spdy/spdy_session_pool.cc
+++ b/net/spdy/spdy_session_pool.cc
@@ -371,10 +371,6 @@ void SpdySessionPool::OnCertDBChanged(const X509Certificate* cert) {
 void SpdySessionPool::DumpMemoryStats(
     base::trace_event::ProcessMemoryDump* pmd,
     const std::string& parent_dump_absolute_name) const {
-  std::string dump_name = base::StringPrintf("%s/spdy_session_pool",
-                                             parent_dump_absolute_name.c_str());
-  base::trace_event::MemoryAllocatorDump* dump =
-      pmd->CreateAllocatorDump(dump_name);
   size_t total_size = 0;
   size_t buffer_size = 0;
   size_t cert_count = 0;
@@ -391,6 +387,11 @@ void SpdySessionPool::DumpMemoryStats(
     if (is_session_active)
       num_active_sessions++;
   }
+  if (sessions_.empty())

[ssid, 2017/01/20 21:35:58]

Could do this at the start of the function.  But why do we want to record if
total is 0, but sessions_ is not empty?

[xunjieli, 2017/01/20 21:45:26]

Done. Good point!

+    return;
+  base::trace_event::MemoryAllocatorDump* dump =
+      pmd->CreateAllocatorDump(base::StringPrintf(
+          "%s/spdy_session_pool", parent_dump_absolute_name.c_str()));
   dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
                   base::trace_event::MemoryAllocatorDump::kUnitsBytes,
                   total_size);