Do not create sub MemoryAllocatorDumps in SSLClientSessionCache

SSLClientSessionCache::DumpMemoryStats() creates one
MemoryAllocatorDump for each cache entry. To make the memory dump lighter,
this CL dumps the total size and count and does not create sub dumps.

BUG=669108

Review-Url: https://codereview.chromium.org/2574513002
Cr-Commit-Position: refs/heads/master@{#437981}

net/ssl/ssl_client_session_cache.cc

@@ -98,31 +98,30 @@ void SSLClientSessionCache::DumpMemoryStats(
     return;
   cache_dump = pmd->CreateAllocatorDump(absolute_name);
   base::AutoLock lock(lock_);
+  int total_serialized_cert_size = 0;
+  int total_cert_count = 0;
   for (const auto& pair : cache_) {
     auto entry = pair.second.get();
     auto cert_chain = entry->x509_chain;
     size_t cert_count = sk_X509_num(cert_chain);
-    base::trace_event::MemoryAllocatorDump* entry_dump =
-        pmd->CreateAllocatorDump(
-            base::StringPrintf("%s/entry_%p", absolute_name.c_str(), entry));
-    int cert_size = 0;
+    total_cert_count += cert_count;
     for (size_t i = 0; i < cert_count; ++i) {
       X509* cert = sk_X509_value(cert_chain, i);
-      cert_size += i2d_X509(cert, nullptr);
+      total_serialized_cert_size += i2d_X509(cert, nullptr);
     }
-    // This measures the lower bound of the serialized certificate. It doesn't
-    // measure the actual memory used, which is 4x this amount (see
-    // crbug.com/671420 for more details).
-    entry_dump->AddScalar("cert_size",
-                          base::trace_event::MemoryAllocatorDump::kUnitsBytes,
-                          cert_size);
-    entry_dump->AddScalar("serialized_cert_count",
-                          base::trace_event::MemoryAllocatorDump::kUnitsObjects,
-                          cert_count);
-    entry_dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
-                          base::trace_event::MemoryAllocatorDump::kUnitsBytes,
-                          cert_size);
   }
+  // This measures the lower bound of the serialized certificate. It doesn't
+  // measure the actual memory used, which is 4x this amount (see
+  // crbug.com/671420 for more details).
+  cache_dump->AddScalar("serialized_cert_size",
+                        base::trace_event::MemoryAllocatorDump::kUnitsBytes,
+                        total_serialized_cert_size);
+  cache_dump->AddScalar("cert_count",
+                        base::trace_event::MemoryAllocatorDump::kUnitsObjects,
+                        total_cert_count);
+  cache_dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
+                        base::trace_event::MemoryAllocatorDump::kUnitsBytes,
+                        total_serialized_cert_size);
 }
 
 void SSLClientSessionCache::FlushExpiredSessions() {

net/ssl/ssl_client_session_cache_unittest.cc

@@ -11,6 +11,7 @@
 #include "base/time/time.h"
 #include "base/trace_event/memory_allocator_dump.h"
 #include "base/trace_event/process_memory_dump.h"
+#include "base/trace_event/trace_event_argument.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/boringssl/src/include/openssl/ssl.h"
 
@@ -325,16 +326,16 @@ TEST(SSLClientSessionCacheTest, TestDumpMemoryStats) {
       new base::trace_event::ProcessMemoryDump(nullptr, dump_args));
   cache.DumpMemoryStats(process_memory_dump.get());
 
-  const base::trace_event::ProcessMemoryDump::AllocatorDumpsMap&
-      allocator_dumps = process_memory_dump->allocator_dumps();
-
-  size_t num_entry_dump = 0;
-  for (const auto& pair : allocator_dumps) {
-    const std::string& dump_name = pair.first;
-    if (dump_name.find("net/ssl_session_cache/entry") != std::string::npos)
-      num_entry_dump++;
-  }
-  ASSERT_EQ(3u, num_entry_dump);
+  const base::trace_event::MemoryAllocatorDump* dump =
+      process_memory_dump->GetAllocatorDump("net/ssl_session_cache");
+  ASSERT_NE(nullptr, dump);
+  std::unique_ptr<base::Value> raw_attrs =
+      dump->attributes_for_testing()->ToBaseValue();
+  base::DictionaryValue* attrs;
+  ASSERT_TRUE(raw_attrs->GetAsDictionary(&attrs));
+  ASSERT_TRUE(attrs->HasKey("cert_count"));
+  ASSERT_TRUE(attrs->HasKey("serialized_cert_size"));
+  ASSERT_TRUE(attrs->HasKey(base::trace_event::MemoryAllocatorDump::kNameSize));
 }
 
 }  // namespace net