Revert of [tracing] Add native allocation tracing mode.

base/trace_event/heap_profiler_allocation_context_tracker.h

Index: base/trace_event/heap_profiler_allocation_context_tracker.h
diff --git a/base/trace_event/heap_profiler_allocation_context_tracker.h b/base/trace_event/heap_profiler_allocation_context_tracker.h
index a310cefc77e2546ea0a1db002b67d5bf35f6a05b..632a4eface8740a9415337c41c6d9874fb107367 100644
--- a/base/trace_event/heap_profiler_allocation_context_tracker.h
+++ b/base/trace_event/heap_profiler_allocation_context_tracker.h
@@ -9,18 +9,9 @@
 
 #include "base/atomicops.h"
 #include "base/base_export.h"
-#include "base/debug/debugging_flags.h"
-#include "base/debug/stack_trace.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/trace_event/heap_profiler_allocation_context.h"
-
-#if HAVE_TRACE_STACK_FRAME_POINTERS && !defined(OS_NACL) && \
-    (BUILDFLAG(ENABLE_PROFILING) || !defined(NDEBUG))
-#define ENABLE_NATIVE_ALLOCATION_TRACES 1
-#else
-#define ENABLE_NATIVE_ALLOCATION_TRACES 0
-#endif
 
 namespace base {
 namespace trace_event {
@@ -32,32 +23,24 @@
 // details.
 class BASE_EXPORT AllocationContextTracker {
  public:
-  enum class CaptureMode: int32_t {
-    DISABLED,       // Don't capture anything
-    PSEUDO_STACK,   // GetContextSnapshot() returns pseudo stack trace
-#if ENABLE_NATIVE_ALLOCATION_TRACES
-    NATIVE_STACK    // GetContextSnapshot() returns native (real) stack trace
-#endif
-  };
+  // Globally enables capturing allocation context.
+  // TODO(ruuda): Should this be replaced by |EnableCapturing| in the future?
+  // Or at least have something that guards agains enable -> disable -> enable?
+  static void SetCaptureEnabled(bool enabled);
 
-  // Globally sets capturing mode.
-  // TODO(primiano): How to guard against *_STACK -> DISABLED -> *_STACK?
-  static void SetCaptureMode(CaptureMode mode);
-
-  // Returns global capturing mode.
-  inline static CaptureMode capture_mode() {
+  // Returns whether capturing allocation context is enabled globally.
+  inline static bool capture_enabled() {
     // A little lag after heap profiling is enabled or disabled is fine, it is
     // more important that the check is as cheap as possible when capturing is
     // not enabled, so do not issue a memory barrier in the fast path.
-    if (subtle::NoBarrier_Load(&capture_mode_) ==
-            static_cast<int32_t>(CaptureMode::DISABLED))
-      return CaptureMode::DISABLED;
+    if (subtle::NoBarrier_Load(&capture_enabled_) == 0)
+      return false;
 
     // In the slow path, an acquire load is required to pair with the release
-    // store in |SetCaptureMode|. This is to ensure that the TLS slot for
+    // store in |SetCaptureEnabled|. This is to ensure that the TLS slot for
     // the thread-local allocation context tracker has been initialized if
-    // |capture_mode| returns something other than DISABLED.
-    return static_cast<CaptureMode>(subtle::Acquire_Load(&capture_mode_));
+    // |capture_enabled| returns true.
+    return subtle::Acquire_Load(&capture_enabled_) != 0;
   }
 
   // Returns the thread-local instance, creating one if necessary. Returns
@@ -97,7 +80,7 @@
  private:
   AllocationContextTracker();
 
-  static subtle::Atomic32 capture_mode_;
+  static subtle::Atomic32 capture_enabled_;
 
   // The pseudo stack where frames are |TRACE_EVENT| names.
   std::vector<const char*> pseudo_stack_;