Revert of Change memory dumps to not use periodic dumps by default.

base/trace_event/memory_dump_manager_unittest.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/memory_dump_manager.h"
 
 #include <stdint.h>
 
 #include <memory>
 #include <utility>
@@ skipping 962 matching lines @@
   EXPECT_FALSE(IsPeriodicDumpingEnabled());
   DisableTracing();
 }
 
 TEST_F(MemoryDumpManagerTest, TraceConfigExpectationsWhenIsCoordinator) {
   InitializeMemoryDumpManager(true /* is_coordinator */);
   ON_CALL(global_dump_handler_, RequestGlobalMemoryDump(_, _))
       .WillByDefault(Return());
 
   // Enabling memory-infra with the legacy TraceConfig (category filter) in
-  // a coordinator process should not enable periodic dumps.
+  // a coordinator process should enable periodic dumps.
   EnableTracingWithLegacyCategories(MemoryDumpManager::kTraceCategory);
-  EXPECT_FALSE(IsPeriodicDumpingEnabled());
+  EXPECT_TRUE(IsPeriodicDumpingEnabled());
   DisableTracing();
 
   // Enabling memory-infra with the new (JSON) TraceConfig in a coordinator
-  // process while specifying a "memory_dump_config" section should enable
+  // process without specifying any "memory_dump_config" section should enable
   // periodic dumps. This is to preserve the behavior chrome://tracing UI, that
-  // is: ticking memory-infra should dump periodically with an explicit config.
+  // is: ticking memory-infra should dump periodically with the default config.
   EnableTracingWithTraceConfig(
-      TraceConfigMemoryTestUtil::GetTraceConfig_PeriodicTriggers(100, 5));
+      TraceConfigMemoryTestUtil::GetTraceConfig_NoTriggers());
   EXPECT_TRUE(IsPeriodicDumpingEnabled());
   DisableTracing();
 
   // Enabling memory-infra with the new (JSON) TraceConfig in a coordinator
   // process with an empty "memory_dump_config" should NOT enable periodic
   // dumps. This is the way telemetry is supposed to use memory-infra with
   // only explicitly triggered dumps.
   EnableTracingWithTraceConfig(
       TraceConfigMemoryTestUtil::GetTraceConfig_EmptyTriggers());
   EXPECT_FALSE(IsPeriodicDumpingEnabled());
@@ skipping 398 matching lines @@
   EXPECT_EQ(3u, result.chrome_dump.v8_total_kb);
   // partition_alloc has partition_alloc/allocated_objects/* which is a subset
   // of partition_alloc/partitions/* so we only count the latter.
   EXPECT_EQ(4u, result.chrome_dump.partition_alloc_total_kb);
   // resident_set_kb should read from process_totals.
   EXPECT_EQ(5u, result.os_dump.resident_set_kb);
 };
 
 }  // namespace trace_event
 }  // namespace base