Implement sampling profiler (chromium side change)

base/debug/trace_event_impl.h

Index: base/debug/trace_event_impl.h
diff --git a/base/debug/trace_event_impl.h b/base/debug/trace_event_impl.h
index 61794807a41323a2f7e29d2addbc101973a072c1..7dd4a00fd251a70ff0d8c24679f8d955252b44c1 100644
--- a/base/debug/trace_event_impl.h
+++ b/base/debug/trace_event_impl.h
@@ -354,6 +354,12 @@ class TraceSamplingThread;
 
 class BASE_EXPORT TraceLog {
  public:
+  enum Mode {
+    DISABLED = 0,
+    RECORDING_MODE,
+    MONITORING_MODE,
+  };
+
   // Options determines how the trace buffer stores data.
   enum Options {
     // Record until the trace buffer is full.
@@ -366,21 +372,21 @@ class BASE_EXPORT TraceLog {
     // Enable the sampling profiler in the recording mode.
     ENABLE_SAMPLING = 1 << 2,
 
-    // Enable the sampling profiler in the monitoring mode.
-    MONITOR_SAMPLING = 1 << 3,
-
     // Echo to console. Events are discarded.
-    ECHO_TO_CONSOLE = 1 << 4,
+    ECHO_TO_CONSOLE = 1 << 3,
   };
 
   // The pointer returned from GetCategoryGroupEnabledInternal() points to a
   // value with zero or more of the following bits. Used in this class only.
   // The TRACE_EVENT macros should only use the value as a bool.
+  // These values must be in sync with macro values in TraceEvent.h in Blink.

[dsinclair, 2013/12/20 14:42:29]

Has this change happened in blink already?

[haraken, 2013/12/25 07:52:31]

Not yet. I'll do it after landing this CL. Since no one is using the monitoring
mode, I think there is no harm in landing this CL first.

   enum CategoryGroupEnabledFlags {
-    // Normal enabled flag for category groups enabled by SetEnabled().
+    // Category group enabled for the recording mode.
     ENABLED_FOR_RECORDING = 1 << 0,
+    // Category group enabled for the monitoring mode.
+    ENABLED_FOR_MONITORING = 1 << 1,
     // Category group enabled by SetEventCallbackEnabled().
-    ENABLED_FOR_EVENT_CALLBACK = 1 << 1,
+    ENABLED_FOR_EVENT_CALLBACK = 1 << 2,
   };
 
   static TraceLog* GetInstance();
@@ -400,12 +406,13 @@ class BASE_EXPORT TraceLog {
   // See CategoryFilter comments for details on how to control what categories
   // will be traced. If tracing has already been enabled, |category_filter| will
   // be merged into the current category filter.
-  void SetEnabled(const CategoryFilter& category_filter, Options options);
+  void SetEnabled(const CategoryFilter& category_filter,
+                  Mode mode, Options options);
 
   // Disables normal tracing for all categories.
   void SetDisabled();
 
-  bool IsEnabled() { return enabled_; }
+  bool IsEnabled() { return mode_ != DISABLED; }
 
   // The number of times we have begun recording traces. If tracing is off,
   // returns -1. If tracing is on, then it returns the number of times we have
@@ -426,7 +433,7 @@ class BASE_EXPORT TraceLog {
   class EnabledStateObserver {
    public:
     // Called just after the tracing system becomes enabled, outside of the
-    // |lock_|.  TraceLog::IsEnabled() is true at this point.
+    // |lock_|. TraceLog::IsEnabled() is true at this point.
     virtual void OnTraceLogEnabled() = 0;
 
     // Called just after the tracing system disables, outside of the |lock_|.
@@ -591,9 +598,9 @@ class BASE_EXPORT TraceLog {
   // by the Singleton class.
   friend struct DefaultSingletonTraits<TraceLog>;
 
-  // Enable/disable each category group based on the current enabled_,
+  // Enable/disable each category group based on the current mode_,
   // category_filter_, event_callback_ and event_callback_category_filter_.
-  // Enable the category group if enabled_ is true and category_filter_ matches
+  // Enable the category group in the enabled mode if category_filter_ matches
   // the category group, or event_callback_ is not null and
   // event_callback_category_filter_ matches the category group.
   void UpdateCategoryGroupEnabledFlags();
@@ -652,7 +659,7 @@ class BASE_EXPORT TraceLog {
   // and thread_colors_.
   Lock thread_info_lock_;
   int locked_line_;
-  bool enabled_;
+  Mode mode_;
   int num_traces_recorded_;
   scoped_ptr<TraceBuffer> logged_events_;
   subtle::AtomicWord /* EventCallback */ event_callback_;