Reland of "[tracing] Add browser-side tests for memory dumps."

base/trace_event/memory_dump_manager.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 <algorithm>
 
 #include "base/atomic_sequence_num.h"
 #include "base/command_line.h"
@@ skipping 79 matching lines @@
   if (instance)
     instance->skip_core_dumpers_auto_registration_for_testing_ = true;
   g_instance_for_testing = instance;
 }
 
 MemoryDumpManager::MemoryDumpManager()
     : delegate_(nullptr),
       memory_tracing_enabled_(0),
       tracing_process_id_(kInvalidTracingProcessId),
       system_allocator_pool_name_(nullptr),
-      skip_core_dumpers_auto_registration_for_testing_(false) {
+      skip_core_dumpers_auto_registration_for_testing_(false),
+      disable_periodic_dumps_for_testing_(false) {
   g_next_guid.GetNext();  // Make sure that first guid is not zero.
 }
 
 MemoryDumpManager::~MemoryDumpManager() {
   base::trace_event::TraceLog::GetInstance()->RemoveEnabledStateObserver(this);
 }
 
 void MemoryDumpManager::Initialize() {
   TRACE_EVENT0(kTraceCategory, "init");  // Add to trace-viewer category list.
   trace_event::TraceLog::GetInstance()->AddEnabledStateObserver(this);
@@ skipping 305 matching lines @@
   for (auto it = dump_providers_.begin(); it != dump_providers_.end(); ++it) {
     it->disabled = false;
     it->consecutive_failures = 0;
   }
 
   subtle::NoBarrier_Store(&memory_tracing_enabled_, 1);
 
   // TODO(primiano): This is a temporary hack to disable periodic memory dumps
   // when running memory benchmarks until they can be enabled/disabled in
   // base::trace_event::TraceConfig. See https://goo.gl/5Hj3o0.
+  // The same mechanism should be used to disable periodic dumps in tests.
   if (delegate_->IsCoordinatorProcess() &&
       !CommandLine::ForCurrentProcess()->HasSwitch(
-          "enable-memory-benchmarking")) {
+          "enable-memory-benchmarking") &&
+      !disable_periodic_dumps_for_testing_) {
     g_periodic_dumps_count = 0;
     periodic_dump_timer_.Start(FROM_HERE,
                                TimeDelta::FromMilliseconds(kDumpIntervalMs),
                                base::Bind(&RequestPeriodicGlobalDump));
   }
 }
 
 void MemoryDumpManager::OnTraceLogDisabled() {
   AutoLock lock(lock_);
   periodic_dump_timer_.Stop();
@@ skipping 34 matching lines @@
       next_dump_provider(next_dump_provider),
       callback(callback),
       task_runner(MessageLoop::current()->task_runner()) {
 }
 
 MemoryDumpManager::ProcessMemoryDumpAsyncState::~ProcessMemoryDumpAsyncState() {
 }
 
 }  // namespace trace_event
 }  // namespace base