Revert of Add EnabledStateObserver to BackgroundTracingManager

content/browser/tracing/background_tracing_manager_impl.cc

Index: content/browser/tracing/background_tracing_manager_impl.cc
diff --git a/content/browser/tracing/background_tracing_manager_impl.cc b/content/browser/tracing/background_tracing_manager_impl.cc
index f42a5e19e9afa039fcc13020391939fe139e51f6..51ebefe377e375f40ffb3491a704f17f283c5c3a 100644
--- a/content/browser/tracing/background_tracing_manager_impl.cc
+++ b/content/browser/tracing/background_tracing_manager_impl.cc
@@ -15,7 +15,6 @@
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
-#include "content/browser/tracing/background_memory_tracing_observer.h"
 #include "content/browser/tracing/background_tracing_rule.h"
 #include "content/browser/tracing/tracing_controller_impl.h"
 #include "content/public/browser/browser_thread.h"
@@ -51,6 +50,14 @@
                             NUMBER_OF_BACKGROUND_TRACING_METRICS);
 }
 
+// Tracing enabled callback for BENCHMARK_MEMORY_LIGHT category preset.
+void BenchmarkMemoryLight_TracingEnabledCallback() {
+  auto* dump_manager = base::trace_event::MemoryDumpManager::GetInstance();
+  dump_manager->RequestGlobalDump(
+      base::trace_event::MemoryDumpType::EXPLICITLY_TRIGGERED,
+      base::trace_event::MemoryDumpLevelOfDetail::BACKGROUND);
+}
+
 }  // namespace
 
 BackgroundTracingManagerImpl::TracingTimer::TracingTimer(
@@ -93,9 +100,7 @@
       is_tracing_(false),
       requires_anonymized_data_(true),
       trigger_handle_ids_(0),
-      triggered_named_event_handle_(-1) {
-  AddEnabledStateObserver(BackgroundMemoryTracingObserver::GetInstance());
-}
+      triggered_named_event_handle_(-1) {}
 
 BackgroundTracingManagerImpl::~BackgroundTracingManagerImpl() {
   NOTREACHED();
@@ -188,40 +193,14 @@
     }
   }
 
-  // Notify observers before starting tracing.
-  for (auto* observer : background_tracing_observer_list_)
-    observer->OnScenarioActivated(*config_);
-
   StartTracingIfConfigNeedsIt();
+
   RecordBackgroundTracingMetric(SCENARIO_ACTIVATED_SUCCESSFULLY);
   return true;
 }
 
 bool BackgroundTracingManagerImpl::HasActiveScenario() {
   return !!config_;
-}
-
-void BackgroundTracingManagerImpl::OnStartTracingDone(
-    BackgroundTracingConfigImpl::CategoryPreset preset) {
-  DCHECK(BrowserThread::CurrentlyOn(content::BrowserThread::UI));
-  for (auto* observer : background_tracing_observer_list_)
-    observer->OnTracingEnabled(preset);
-}
-
-void BackgroundTracingManagerImpl::AddEnabledStateObserver(
-    EnabledStateObserver* observer) {
-  DCHECK(BrowserThread::CurrentlyOn(content::BrowserThread::UI));
-  background_tracing_observer_list_.push_back(observer);
-}
-
-void BackgroundTracingManagerImpl::RemoveEnabledStateObserver(
-    EnabledStateObserver* observer) {
-  DCHECK(BrowserThread::CurrentlyOn(content::BrowserThread::UI));
-  std::vector<EnabledStateObserver*>::iterator it =
-      std::find(background_tracing_observer_list_.begin(),
-                background_tracing_observer_list_.end(), observer);
-  if (it != background_tracing_observer_list_.end())
-    background_tracing_observer_list_.erase(it);
 }
 
 bool BackgroundTracingManagerImpl::IsTracingForTesting() {
@@ -411,6 +390,11 @@
   trigger_handles_.clear();
 }
 
+void BackgroundTracingManagerImpl::SetTracingEnabledCallbackForTesting(
+    const base::Closure& callback) {
+  tracing_enabled_callback_for_testing_ = callback;
+};
+
 void BackgroundTracingManagerImpl::SetRuleTriggeredCallbackForTesting(
     const base::Closure& callback) {
   rule_triggered_callback_for_testing_ = callback;
@@ -429,22 +413,26 @@
   if (requires_anonymized_data_)
     trace_config.EnableArgumentFilter();
 
-  if (preset ==
-      BackgroundTracingConfigImpl::CategoryPreset::BENCHMARK_MEMORY_LIGHT) {
-    // On memory light mode, the periodic memory dumps are disabled.
-    // TODO(ssid): Remove this when memory-infra supports peak detection
-    // crbug.com/609935.
+  base::Closure tracing_enabled_callback;
+  if (!tracing_enabled_callback_for_testing_.is_null()) {
+    tracing_enabled_callback = tracing_enabled_callback_for_testing_;
+  } else if (preset == BackgroundTracingConfigImpl::CategoryPreset::
+                           BENCHMARK_MEMORY_LIGHT) {
+    // On memory light mode, the periodic memory dumps are disabled and a single
+    // memory dump is requested after tracing is enabled in all the processes.
+    // TODO(ssid): Remove this when background tracing supports trace config
+    // strings and memory-infra supports peak detection crbug.com/609935.
     base::trace_event::TraceConfig::MemoryDumpConfig memory_config;
     memory_config.allowed_dump_modes =
         std::set<base::trace_event::MemoryDumpLevelOfDetail>(
             {base::trace_event::MemoryDumpLevelOfDetail::BACKGROUND});
     trace_config.ResetMemoryDumpConfig(memory_config);
+    tracing_enabled_callback =
+        base::Bind(&BenchmarkMemoryLight_TracingEnabledCallback);
   }
 
   is_tracing_ = TracingController::GetInstance()->StartTracing(
-      trace_config,
-      base::Bind(&BackgroundTracingManagerImpl::OnStartTracingDone,
-                 base::Unretained(this), preset));
+      trace_config, tracing_enabled_callback);
   RecordBackgroundTracingMetric(RECORDING_ENABLED);
 }