Disable timing from chrome://profiler on Android.

base/tracked_objects.cc

Index: base/tracked_objects.cc
diff --git a/base/tracked_objects.cc b/base/tracked_objects.cc
index 0847d5f9163622cd65449707775fe7594de9a2b1..def7f2ebdf8b2d56e109b29a8f0e1a216ee4040e 100644
--- a/base/tracked_objects.cc
+++ b/base/tracked_objects.cc
@@ -7,6 +7,8 @@
 #include <limits.h>
 #include <stdlib.h>
 
+#include "base/base_switches.h"
+#include "base/command_line.h"
 #include "base/compiler_specific.h"
 #include "base/debug/leak_annotations.h"
 #include "base/logging.h"
@@ -51,6 +53,27 @@ const ThreadData::Status kInitialStartupState =
 // problem with its presence).
 static const bool kAllowAlternateTimeSourceHandling = true;
 
+// Control whether to collect timing information.
+enum ProfilerTimingState {

[Mark Mentovai, 2013/12/09 14:18:32]

You can move this whole enum definition and variable declaration to be in-line
in IsProfilerTimingEnabled.

The enum can also be anonymous, it doesn’t need to have a type name.

[qsr, 2013/12/09 14:48:32]

Done.

+  UNDEFINED_TIMING,
+  ENABLED_TIMING,
+  DISABLED_TIMING,
+} g_timing_enabled = UNDEFINED_TIMING;
+
+inline bool IsProfilerTimingEnabled() {
+  // This initialization is not thread-safe, so the value of |g_timing_enabled|
+  // can be computed multiple time. This is not an issue, as the computed value

[Mark Mentovai, 2013/12/09 14:18:32]

time→times

[qsr, 2013/12/09 14:48:32]

Done.

+  // will always be the same, and is side-effect free.
+  if (g_timing_enabled == UNDEFINED_TIMING) {
+    g_timing_enabled = (CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
+                            switches::kProfilerTiming) ==
+                        switches::kProfilerTimingDisabledValue)
+                           ? DISABLED_TIMING
+                           : ENABLED_TIMING;
+  }
+  return g_timing_enabled == ENABLED_TIMING;
+}
+
 }  // namespace
 
 //------------------------------------------------------------------------------
@@ -754,7 +777,7 @@ void ThreadData::SetAlternateTimeSource(NowFunction* now_function) {
 TrackedTime ThreadData::Now() {
   if (kAllowAlternateTimeSourceHandling && now_function_)
     return TrackedTime::FromMilliseconds((*now_function_)());
-  if (kTrackAllTaskObjects && TrackingStatus())
+  if (kTrackAllTaskObjects && IsProfilerTimingEnabled() && TrackingStatus())
     return TrackedTime::Now();
   return TrackedTime();  // Super fast when disabled, or not compiled.
 }