Implement CPU time for OS X and POSIX.

test/unittests/base/platform/time-unittest.cc

Index: test/unittests/base/platform/time-unittest.cc
diff --git a/test/unittests/base/platform/time-unittest.cc b/test/unittests/base/platform/time-unittest.cc
index b3bfbab3190506029b0243359520f913121cce59..784fbf842d92b39df06ed568294c4346e7a4d178 100644
--- a/test/unittests/base/platform/time-unittest.cc
+++ b/test/unittests/base/platform/time-unittest.cc
@@ -16,6 +16,7 @@
 #endif
 
 #include "src/base/platform/elapsed-timer.h"
+#include "src/base/platform/platform.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace v8 {
@@ -182,5 +183,32 @@ TEST(TimeTicks, IsMonotonic) {
   }
 }
 
+
+// Disable on windows until it is implemented.
+#if V8_OS_ANDROID || V8_OS_WIN

[fmeawad, 2016/05/09 23:24:56]

Why are you disabling the test on Android?

[lpy, 2016/05/09 23:51:15]

This test is ported from Chrome, and Chrome disables it on Android.

+#define MAYBE_ThreadNow DISABLED_ThreadNow
+#else
+#define MAYBE_ThreadNow ThreadNow
+#endif
+TEST(ThreadTicks, MAYBE_ThreadNow) {
+  if (ThreadTicks::IsSupported()) {

[fmeawad, 2016/05/09 23:24:56]

How about testing IsSupported itself?

[lpy, 2016/05/09 23:51:15]

Is it necessary? ThreadTicks::IsSupported doesn't do any calculation, just
returns true when some macros are defined and false otherwise.

[fmeawad, 2016/05/10 18:12:48]

It is very necessary, but I cannot think of a good testing strategy. The problem
with this test as it stands is that if IsSupported is buggy and always returns
false we also loose coverage for ::Now()

+    TimeTicks begin = TimeTicks::Now();
+    ThreadTicks begin_thread = ThreadTicks::Now();
+    // Make sure that ThreadNow value is non-zero.
+    EXPECT_GT(begin_thread, ThreadTicks());
+    // Sleep for 10 milliseconds to get the thread de-scheduled.
+    OS::Sleep(base::TimeDelta::FromMilliseconds(10));
+    ThreadTicks end_thread = ThreadTicks::Now();
+    TimeTicks end = TimeTicks::Now();
+    TimeDelta delta = end - begin;
+    TimeDelta delta_thread = end_thread - begin_thread;
+    // Make sure that some thread time have elapsed.
+    EXPECT_GT(delta_thread.InMicroseconds(), 0);
+    // But the thread time is at least 9ms less than clock time.
+    TimeDelta difference = delta - delta_thread;
+    EXPECT_GE(difference.InMicroseconds(), 9000);
+  }
+}
+
 }  // namespace base
 }  // namespace v8