Revert of Implement CPU time for OS X and POSIX.

src/base/platform/time.cc

Index: src/base/platform/time.cc
diff --git a/src/base/platform/time.cc b/src/base/platform/time.cc
index 9576785974629933813836df51b137a5707500dd..6d5e538970cfd8e8b3608c196b79c361a44c4107 100644
--- a/src/base/platform/time.cc
+++ b/src/base/platform/time.cc
@@ -10,9 +10,7 @@
 #include <unistd.h>
 #endif
 #if V8_OS_MACOSX
-#include <mach/mach.h>
 #include <mach/mach_time.h>
-#include <pthread.h>
 #endif
 
 #include <cstring>
@@ -26,51 +24,6 @@
 #include "src/base/cpu.h"
 #include "src/base/logging.h"
 #include "src/base/platform/platform.h"
-
-namespace {
-
-#if V8_OS_MACOSX
-int64_t ComputeThreadTicks() {
-  mach_msg_type_number_t thread_info_count = THREAD_BASIC_INFO_COUNT;
-  thread_basic_info_data_t thread_info_data;
-  kern_return_t kr = thread_info(
-      pthread_mach_thread_np(pthread_self()),
-      THREAD_BASIC_INFO,
-      reinterpret_cast<thread_info_t>(&thread_info_data),
-      &thread_info_count);
-  DCHECK(kr == KERN_SUCCESS);
-
-  v8::base::CheckedNumeric<int64_t> absolute_micros(
-      thread_info_data.user_time.seconds);
-  absolute_micros *= v8::base::Time::kMicrosecondsPerSecond;
-  absolute_micros += thread_info_data.user_time.microseconds;
-  return absolute_micros.ValueOrDie();
-}
-#elif V8_OS_POSIX
-// Helper function to get results from clock_gettime() and convert to a
-// microsecond timebase. Minimum requirement is MONOTONIC_CLOCK to be supported
-// on the system. FreeBSD 6 has CLOCK_MONOTONIC but defines
-// _POSIX_MONOTONIC_CLOCK to -1.
-inline int64_t ClockNow(clockid_t clk_id) {
-#if (defined(_POSIX_MONOTONIC_CLOCK) && _POSIX_MONOTONIC_CLOCK >= 0) || \
-  defined(V8_OS_BSD) || defined(V8_OS_ANDROID)
-  struct timespec ts;
-  if (clock_gettime(clk_id, &ts) != 0) {
-    UNREACHABLE();
-    return 0;
-  }
-  v8::base::internal::CheckedNumeric<int64_t> result(ts.tv_sec);
-  result *= v8::base::Time::kMicrosecondsPerSecond;
-  result += (ts.tv_nsec / v8::base::Time::kNanosecondsPerMicrosecond);
-  return result.ValueOrDie();
-#else  // Monotonic clock not supported.
-  return 0;
-#endif
-}
-#endif  // V8_OS_MACOSX
-
-
-}  // namespace
 
 namespace v8 {
 namespace base {
@@ -588,7 +541,12 @@
 #elif V8_OS_SOLARIS
   ticks = (gethrtime() / Time::kNanosecondsPerMicrosecond);
 #elif V8_OS_POSIX
-  ticks = ClockNow(CLOCK_MONOTONIC);
+  struct timespec ts;
+  int result = clock_gettime(CLOCK_MONOTONIC, &ts);
+  DCHECK_EQ(0, result);
+  USE(result);
+  ticks = (ts.tv_sec * Time::kMicrosecondsPerSecond +
+           ts.tv_nsec / Time::kNanosecondsPerMicrosecond);
 #endif  // V8_OS_MACOSX
   // Make sure we never return 0 here.
   return TimeTicks(ticks + 1);
@@ -602,30 +560,5 @@
 
 #endif  // V8_OS_WIN
 
-
-// TODO(lpy): For windows ThreadTicks implementation,
-// see http://crbug.com/v8/5000
-bool ThreadTicks::IsSupported() {
-#if (defined(_POSIX_THREAD_CPUTIME) && (_POSIX_THREAD_CPUTIME >= 0)) || \
-    defined(V8_OS_MACOSX) || defined(V8_OS_ANDROID)
-    return true;
-#else
-    return false;
-#endif
-}
-
-
-ThreadTicks ThreadTicks::Now() {
-#if V8_OS_MACOSX
-  return ThreadTicks(ComputeThreadTicks());
-#elif(defined(_POSIX_THREAD_CPUTIME) && (_POSIX_THREAD_CPUTIME >= 0)) || \
-  defined(V8_OS_ANDROID)
-  return ThreadTicks(ClockNow(CLOCK_THREAD_CPUTIME_ID));
-#else
-  UNREACHABLE();
-  return ThreadTicks();
-#endif
-}
-
 }  // namespace base
 }  // namespace v8