Revert of Initialize the now_funciton to the HighResNowWrapper in case High...

Revert of Initialize the now_funciton to the HighResNowWrapper in case High Res is supported (patchset #7 of https://codereview.chromium.org/446203002/)

Reason for revert:
It causes a Canary crash

https://code.google.com/p/chromium/issues/detail?id=408354

The added static initializer causes a crash in libpeerconnetion used by WebRTC

Fix to reland: remove static initializer.

Original issue's description:
> We have noticed a clock shift when QPC was deployed. It shows as a regression on the perf bots
> https://chromeperf.appspot.com/report?masters=ChromiumPerf&bots=chromium-rel-win8-dual&tests=startup.warm.dirty.blank_page%2Fwindow_display_time&rev=286928
>
> It is not a real regression, the initial_time and initial_ticks are not properly initialized when switching to HighResolution (i.e. QPC).
> This CL initializes the now_function to the HighResNowWrapper instead of setting it to RolloverProtectedNow then to the HighResNowWrapper.
>
> By doing that, we avoid getting an incorrect initial_time and initial_ticks using the RolloverProtectedNow and avoid having to reinitialize.
>
> BUG=158234
>
> Committed: https://chromium.googlesource.com/chromium/src/+/10c40c221c314e41add0a5b4df1ee7467681a430

TBR=jar@chromium.org,willchan@chromium.org,maruel@chromium.org,thakis@chromium.org,jam@chromium.org,cpu@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=158234

Review URL: https://codereview.chromium.org/516693002

Cr-Commit-Position: refs/heads/master@{#292288}

base/test/test_suite.cc

@@ -135,6 +135,7 @@ void TestSuite::InitializeFromCommandLine(int argc, wchar_t** argv) {
 void TestSuite::PreInitialize(bool create_at_exit_manager) {
 #if defined(OS_WIN)
   testing::GTEST_FLAG(catch_exceptions) = false;
+  base::TimeTicks::SetNowIsHighResNowIfSupported();
 #endif
   base::EnableTerminationOnHeapCorruption();
 #if defined(OS_LINUX) && defined(USE_AURA)

base/time/time.h

@@ -623,6 +623,14 @@ class BASE_EXPORT TimeTicks {
   // This is only for testing.
   static bool IsHighResClockWorking();
 
+  // Enable high resolution time for TimeTicks::Now(). This function will
+  // test for the availability of a working implementation of
+  // QueryPerformanceCounter(). If one is not available, this function does
+  // nothing and the resolution of Now() remains 1ms. Otherwise, all future
+  // calls to TimeTicks::Now() will have the higher resolution provided by QPC.
+  // Returns true if high resolution time was successfully enabled.
+  static bool SetNowIsHighResNowIfSupported();
+
   // Returns a time value that is NOT rollover protected.
   static TimeTicks UnprotectedNow();
 #endif

base/time/time_win.cc

@@ -373,24 +373,21 @@ bool IsBuggyAthlon(const base::CPU& cpu) {
 class HighResNowSingleton {
  public:
   HighResNowSingleton()
-      : ticks_per_second_(0),
-        skew_(0) {
+    : ticks_per_second_(0),
+      skew_(0) {
+    InitializeClock();
 
     base::CPU cpu;
     if (IsBuggyAthlon(cpu))
-      return;
-
-    // Synchronize the QPC clock with GetSystemTimeAsFileTime.
-    LARGE_INTEGER ticks_per_sec = {0};
-    if (!QueryPerformanceFrequency(&ticks_per_sec))
-      return; // QPC is not available.
-    ticks_per_second_ = ticks_per_sec.QuadPart;
-
-    skew_ = UnreliableNow() - ReliableNow();
+      DisableHighResClock();
   }
 
   bool IsUsingHighResClock() {
-    return ticks_per_second_ != 0;
+    return ticks_per_second_ != 0.0;
+  }
+
+  void DisableHighResClock() {
+    ticks_per_second_ = 0.0;
   }
 
   TimeDelta Now() {
@@ -425,6 +422,16 @@ class HighResNowSingleton {
   }
 
  private:
+  // Synchronize the QPC clock with GetSystemTimeAsFileTime.
+  void InitializeClock() {
+    LARGE_INTEGER ticks_per_sec = {0};
+    if (!QueryPerformanceFrequency(&ticks_per_sec))
+      return;  // Broken, we don't guarantee this function works.
+    ticks_per_second_ = ticks_per_sec.QuadPart;
+
+    skew_ = UnreliableNow() - ReliableNow();
+  }
+
   // Get the number of microseconds since boot in an unreliable fashion.
   int64 UnreliableNow() {
     LARGE_INTEGER now;
@@ -453,6 +460,7 @@ TimeDelta HighResNowWrapper() {
 }
 
 typedef TimeDelta (*NowFunction)(void);
+NowFunction now_function = RolloverProtectedNow;
 
 bool CPUReliablySupportsHighResTime() {
   base::CPU cpu;
@@ -466,14 +474,6 @@ bool CPUReliablySupportsHighResTime() {
   return true;
 }
 
-NowFunction GetNowFunction() {
-  if (!CPUReliablySupportsHighResTime())
-    return RolloverProtectedNow;
-  return HighResNowWrapper;
-}
-
-NowFunction now_function = GetNowFunction();
-
 }  // namespace
 
 // static
@@ -487,6 +487,16 @@ TimeTicks::TickFunctionType TimeTicks::SetMockTickFunction(
   return old;
 }
 
+// static
+bool TimeTicks::SetNowIsHighResNowIfSupported() {
+  if (!CPUReliablySupportsHighResTime()) {
+    return false;
+  }
+
+  now_function = HighResNowWrapper;
+  return true;
+}
+
 // static
 TimeTicks TimeTicks::Now() {
   return TimeTicks() + now_function();

chrome/browser/chrome_browser_main_win.cc

@@ -158,6 +158,7 @@ int DoUninstallTasks(bool chrome_still_running) {
 ChromeBrowserMainPartsWin::ChromeBrowserMainPartsWin(
     const content::MainFunctionParams& parameters)
     : ChromeBrowserMainParts(parameters) {
+  base::TimeTicks::SetNowIsHighResNowIfSupported();
   if (base::win::IsMetroProcess()) {
     typedef const wchar_t* (*GetMetroSwitches)(void);
     GetMetroSwitches metro_switches_proc = reinterpret_cast<GetMetroSwitches>(

content/app/content_main_runner.cc

@@ -666,6 +666,8 @@ class ContentMainRunnerImpl : public ContentMainRunner {
       MachBroker::ChildSendTaskPortToParent();
     }
 #elif defined(OS_WIN)
+    base::TimeTicks::SetNowIsHighResNowIfSupported();
+
     bool init_device_scale_factor = true;
     if (command_line.HasSwitch(switches::kDeviceScaleFactor)) {
       std::string scale_factor_string = command_line.GetSwitchValueASCII(