Explicitly track the time source type in base/profiler/alternate_timer.h

We were previously implicitly tracking the time source as either default or tcmalloc-based; but as we add more time sources (e.g. cpu time), we'll want to have explicit tracking for this.

BUG=none
TEST=none
TBR=jar@chromium.org

(Recommit of [ https://chromiumcodereview.appspot.com/10225017/ ])


Review URL: http://codereview.chromium.org/10248001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@134187 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 22 insertions, 5 deletions

diff --git a/base/allocator/allocator_shim.cc b/base/allocator/allocator_shim.cc
index d61a9a4..075828d 100644
--- a/base/allocator/allocator_shim.cc
+++ b/base/allocator/allocator_shim.cc
@@ -270,7 +270,8 @@ extern "C" int _heap_init() {
       GetenvBeforeMain(tracked_objects::kAlternateProfilerTime);
   if (profiling && *profiling == '1') {
     tracked_objects::SetAlternateTimeSource(
-        tcmalloc::ThreadCache::GetBytesAllocatedOnCurrentThread);
+        tcmalloc::ThreadCache::GetBytesAllocatedOnCurrentThread,
+        tracked_objects::TIME_SOURCE_TYPE_TCMALLOC);
   }
 
   return 1;
diff --git a/base/profiler/alternate_timer.cc b/base/profiler/alternate_timer.cc
index abf9180..4eba89c 100644
--- a/base/profiler/alternate_timer.cc
+++ b/base/profiler/alternate_timer.cc
@@ -9,6 +9,8 @@
 namespace {
 
 tracked_objects::NowFunction* g_time_function = NULL;
+tracked_objects::TimeSourceType g_time_source_type =
+    tracked_objects::TIME_SOURCE_TYPE_WALL_TIME;
 
 }  // anonymous namespace
 
@@ -18,13 +20,18 @@ const char kAlternateProfilerTime[] = "CHROME_PROFILER_TIME";
 
 // Set an alternate timer function to replace the OS time function when
 // profiling.
-void SetAlternateTimeSource(NowFunction* now_function) {
+void SetAlternateTimeSource(NowFunction* now_function, TimeSourceType type) {
   DCHECK_EQ(reinterpret_cast<NowFunction*>(NULL), g_time_function);
   g_time_function = now_function;
+  g_time_source_type = type;
 }
 
 NowFunction* GetAlternateTimeSource() {
   return g_time_function;
 }
 
+TimeSourceType GetTimeSourceType() {
+  return g_time_source_type;
+}
+
 }  // namespace tracked_objects
diff --git a/base/profiler/alternate_timer.h b/base/profiler/alternate_timer.h
index 778dc62..eb0022d 100644
--- a/base/profiler/alternate_timer.h
+++ b/base/profiler/alternate_timer.h
@@ -12,6 +12,11 @@
 
 namespace tracked_objects {
 
+enum BASE_EXPORT TimeSourceType {
+  TIME_SOURCE_TYPE_WALL_TIME,
+  TIME_SOURCE_TYPE_TCMALLOC
+};
+
 // Provide type for an alternate timer function.
 typedef unsigned int NowFunction();
 
@@ -24,11 +29,14 @@ extern const char kAlternateProfilerTime[];
 // profiling.  Typically this is called by an allocator that is providing a
 // function that indicates how much memory has been allocated on any given
 // thread.
-void SetAlternateTimeSource(NowFunction* now_function);
+void SetAlternateTimeSource(NowFunction* now_function, TimeSourceType type);
 
 // Gets the pointer to a function that was set via SetAlternateTimeSource().
 // Returns NULL if no set was done prior to calling GetAlternateTimeSource.
-BASE_EXPORT NowFunction* GetAlternateTimeSource();
+NowFunction* GetAlternateTimeSource();
+
+// Returns the type of the currently set time source.
+BASE_EXPORT TimeSourceType GetTimeSourceType();
 
 }  // namespace tracked_objects
 
diff --git a/chrome/browser/metrics/metrics_log.cc b/chrome/browser/metrics/metrics_log.cc
index 36be84f..b79ecef1 100644
--- a/chrome/browser/metrics/metrics_log.cc
+++ b/chrome/browser/metrics/metrics_log.cc
@@ -787,7 +787,8 @@ void MetricsLog::RecordProfilerData(
     content::ProcessType process_type) {
   DCHECK(!locked());
 
-  if (tracked_objects::GetAlternateTimeSource()) {
+  if (tracked_objects::GetTimeSourceType() !=
+          tracked_objects::TIME_SOURCE_TYPE_WALL_TIME) {
     // We currently only support the default time source, wall clock time.
     return;
   }