Switch to using TimeTicks for profiling and histograms

Avoid using wall clock time, which can be changed by the user,
or impacted by Daylight Savings transitions etc.

BUG=14193
r=eroman
Review URL: http://codereview.chromium.org/1253005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@46821 0039d316-1c4b-4281-b951-d872f2087c98

9 files changed, 27 insertions, 24 deletions

diff --git a/base/spin_wait.h b/base/spin_wait.h
index d6571b7..b1e2045 100644
--- a/base/spin_wait.h
+++ b/base/spin_wait.h
@@ -35,11 +35,11 @@
                                      (expression))
 
 #define SPIN_FOR_TIMEDELTA_OR_UNTIL_TRUE(delta, expression) do { \
-  base::Time start = base::Time::Now(); \
+  base::TimeTicks start = base::TimeTicks::Now(); \
   const base::TimeDelta kTimeout = delta; \
     while (!(expression)) { \
-      if (kTimeout < base::Time::Now() - start) { \
-      EXPECT_LE((base::Time::Now() - start).InMilliseconds(), \
+      if (kTimeout < base::TimeTicks::Now() - start) { \
+      EXPECT_LE((base::TimeTicks::Now() - start).InMilliseconds(), \
                 kTimeout.InMilliseconds()) << "Timed out"; \
         break; \
       } \
diff --git a/base/tracked.cc b/base/tracked.cc
index 34694bb..fdac6d3 100644
--- a/base/tracked.cc
+++ b/base/tracked.cc
@@ -7,7 +7,7 @@
 #include "base/string_util.h"
 #include "base/tracked_objects.h"
 
-using base::Time;
+using base::TimeTicks;
 
 namespace tracked_objects {
 
@@ -56,7 +56,9 @@ void Tracked::ResetBirthTime() {}
 
 #else
 
-Tracked::Tracked() : tracked_births_(NULL), tracked_birth_time_(Time::Now()) {
+Tracked::Tracked()
+    : tracked_births_(NULL),
+      tracked_birth_time_(TimeTicks::Now()) {
   if (!ThreadData::IsActive())
     return;
   SetBirthPlace(Location("NoFunctionName", "NeedToSetBirthPlace", -1));
@@ -66,7 +68,7 @@ Tracked::~Tracked() {
   if (!ThreadData::IsActive() || !tracked_births_)
     return;
   ThreadData::current()->TallyADeath(*tracked_births_,
-                                     Time::Now() - tracked_birth_time_);
+                                     TimeTicks::Now() - tracked_birth_time_);
 }
 
 void Tracked::SetBirthPlace(const Location& from_here) {
@@ -81,7 +83,7 @@ void Tracked::SetBirthPlace(const Location& from_here) {
 }
 
 void Tracked::ResetBirthTime() {
-  tracked_birth_time_ = Time::Now();
+  tracked_birth_time_ = TimeTicks::Now();
 }
 
 bool Tracked::MissingBirthplace() const {
diff --git a/base/tracked.h b/base/tracked.h
index c0c3aee..b0be729 100644
--- a/base/tracked.h
+++ b/base/tracked.h
@@ -116,7 +116,7 @@ class Tracked {
   // The time this object was constructed.  If its life consisted of a long
   // waiting period, and then it became active, then this value is generally
   // reset before the object begins it active life.
-  base::Time tracked_birth_time_;
+  base::TimeTicks tracked_birth_time_;
 
 #endif  // TRACK_ALL_TASK_OBJECTS
 
diff --git a/chrome/browser/safe_browsing/safe_browsing_database.cc b/chrome/browser/safe_browsing/safe_browsing_database.cc
index aa6a97a..3237b30 100644
--- a/chrome/browser/safe_browsing/safe_browsing_database.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_database.cc
@@ -9,7 +9,7 @@
 #include "chrome/browser/safe_browsing/bloom_filter.h"
 #include "chrome/browser/safe_browsing/safe_browsing_database_bloom.h"
 
-using base::Time;
+using base::TimeTicks;
 
 // Filename suffix for the bloom filter.
 static const FilePath::CharType kBloomFilterFile[] =
@@ -47,10 +47,10 @@ void SafeBrowsingDatabase::LoadBloomFilter() {
   }
 
   // We have a bloom filter file, so use that as our filter.
-  Time before = Time::Now();
+  TimeTicks before = TimeTicks::Now();
   bloom_filter_ = BloomFilter::LoadFile(bloom_filter_filename_);
   SB_DLOG(INFO) << "SafeBrowsingDatabase read bloom filter in "
-                << (Time::Now() - before).InMilliseconds() << " ms";
+                << (TimeTicks::Now() - before).InMilliseconds() << " ms";
 
   if (!bloom_filter_.get())
     UMA_HISTOGRAM_COUNTS("SB2.FilterReadFail", 1);
@@ -64,10 +64,10 @@ void SafeBrowsingDatabase::WriteBloomFilter() {
   if (!bloom_filter_.get())
     return;
 
-  Time before = Time::Now();
+  TimeTicks before = TimeTicks::Now();
   bool write_ok = bloom_filter_->WriteFile(bloom_filter_filename_);
   SB_DLOG(INFO) << "SafeBrowsingDatabase wrote bloom filter in " <<
-      (Time::Now() - before).InMilliseconds() << " ms";
+      (TimeTicks::Now() - before).InMilliseconds() << " ms";
 
   if (!write_ok)
     UMA_HISTOGRAM_COUNTS("SB2.FilterWriteFail", 1);
diff --git a/chrome/browser/safe_browsing/safe_browsing_database_bloom.cc b/chrome/browser/safe_browsing/safe_browsing_database_bloom.cc
index 6951e41..8acda7c 100644
--- a/chrome/browser/safe_browsing/safe_browsing_database_bloom.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_database_bloom.cc
@@ -157,7 +157,7 @@ void SafeBrowsingDatabaseBloom::InsertChunks(const std::string& list_name,
   if (chunks.empty())
     return;
 
-  base::Time insert_start = base::Time::Now();
+  base::TimeTicks insert_start = base::TimeTicks::Now();
 
   int list_id = safe_browsing_util::GetListId(list_name);
   ChunkType chunk_type = chunks.front().is_add ? ADD_CHUNK : SUB_CHUNK;
@@ -190,7 +190,7 @@ void SafeBrowsingDatabaseBloom::InsertChunks(const std::string& list_name,
     }
   }
 
-  UMA_HISTOGRAM_TIMES("SB2.ChunkInsert", base::Time::Now() - insert_start);
+  UMA_HISTOGRAM_TIMES("SB2.ChunkInsert", base::TimeTicks::Now() - insert_start);
 }
 
 void SafeBrowsingDatabaseBloom::DeleteChunks(
diff --git a/chrome/test/chrome_process_util.cc b/chrome/test/chrome_process_util.cc
index 8e86e60..a3c4d6f 100644
--- a/chrome/test/chrome_process_util.cc
+++ b/chrome/test/chrome_process_util.cc
@@ -12,8 +12,8 @@
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/result_codes.h"
 
-using base::Time;
 using base::TimeDelta;
+using base::TimeTicks;
 
 void TerminateAllChromeProcesses(base::ProcessId browser_pid) {
   // Total time the function will wait for chrome processes
@@ -38,11 +38,11 @@ void TerminateAllChromeProcesses(base::ProcessId browser_pid) {
   for (it = handles.begin(); it != handles.end(); ++it)
     base::KillProcess(*it, ResultCodes::TASKMAN_KILL, false);
 
-  const Time start = Time::Now();
+  const TimeTicks start = TimeTicks::Now();
   for (it = handles.begin();
-       it != handles.end() && Time::Now() - start < kExitTimeout;
+       it != handles.end() && TimeTicks::Now() - start < kExitTimeout;
        ++it) {
-    int64 wait_time_ms = (Time::Now() - start).InMilliseconds();
+    int64 wait_time_ms = (TimeTicks::Now() - start).InMilliseconds();
     base::WaitForSingleProcess(*it, wait_time_ms);
   }
 
diff --git a/net/base/file_stream_posix.cc b/net/base/file_stream_posix.cc
index 65c8e2b..735f2b8 100644
--- a/net/base/file_stream_posix.cc
+++ b/net/base/file_stream_posix.cc
@@ -223,11 +223,12 @@ FileStream::AsyncContext::~AsyncContext() {
     // still running the IO task, or the completion callback is queued up on the
     // MessageLoopForIO, but AsyncContext() got deleted before then.
     const bool need_to_wait = !background_io_completed_.IsSignaled();
-    base::Time start = base::Time::Now();
+    base::TimeTicks start = base::TimeTicks::Now();
     RunAsynchronousCallback();
     if (need_to_wait) {
       // We want to see if we block the message loop for too long.
-      UMA_HISTOGRAM_TIMES("AsyncIO.FileStreamClose", base::Time::Now() - start);
+      UMA_HISTOGRAM_TIMES("AsyncIO.FileStreamClose",
+                          base::TimeTicks::Now() - start);
     }
   }
 }
diff --git a/net/base/file_stream_win.cc b/net/base/file_stream_win.cc
index 1ad9a34..6a6db90 100644
--- a/net/base/file_stream_win.cc
+++ b/net/base/file_stream_win.cc
@@ -74,14 +74,15 @@ class FileStream::AsyncContext : public MessageLoopForIO::IOHandler {
 FileStream::AsyncContext::~AsyncContext() {
   is_closing_ = true;
   bool waited = false;
-  base::Time start = base::Time::Now();
+  base::TimeTicks start = base::TimeTicks::Now();
   while (callback_) {
     waited = true;
     MessageLoopForIO::current()->WaitForIOCompletion(INFINITE, this);
   }
   if (waited) {
     // We want to see if we block the message loop for too long.
-    UMA_HISTOGRAM_TIMES("AsyncIO.FileStreamClose", base::Time::Now() - start);
+    UMA_HISTOGRAM_TIMES("AsyncIO.FileStreamClose",
+                        base::TimeTicks::Now() - start);
   }
 }
 
diff --git a/net/disk_cache/block_files.cc b/net/disk_cache/block_files.cc
index 3161317..3a87731 100644
--- a/net/disk_cache/block_files.cc
+++ b/net/disk_cache/block_files.cc
@@ -11,7 +11,6 @@
 #include "net/disk_cache/cache_util.h"
 #include "net/disk_cache/file_lock.h"
 
-using base::Time;
 using base::TimeTicks;
 
 namespace {