[Windows] One TimeTicks clock: efficient/reliable high-res, with low-res fallback.

base/time/time_unittest.cc

Index: base/time/time_unittest.cc
diff --git a/base/time/time_unittest.cc b/base/time/time_unittest.cc
index 16d6fe9c3a2918f19d109318f8af605845d3259a..07b1e6b77e704b25fc5198a8c3d4756245ea51aa 100644
--- a/base/time/time_unittest.cc
+++ b/base/time/time_unittest.cc
@@ -6,6 +6,7 @@
 
 #include <time.h>
 
+#include <limits>
 #include <string>
 
 #include "base/compiler_specific.h"
@@ -642,12 +643,10 @@ TEST(TimeTicks, Deltas) {
 }
 
 static void HighResClockTest(TimeTicks (*GetTicks)()) {
-#if defined(OS_WIN)
   // HighResNow doesn't work on some systems.  Since the product still works
   // even if it doesn't work, it makes this entire test questionable.
-  if (!TimeTicks::IsHighResClockWorking())
+  if (!TimeTicks::IsHighResolution())
     return;
-#endif
 
   // Why do we loop here?
   // We're trying to measure that intervals increment in a VERY small amount
@@ -792,6 +791,26 @@ std::string AnyToString(Any any) {
   return oss.str();
 }
 
+TEST(TimeDelta, Magnitude) {
+  const int64 zero = 0;
+  EXPECT_EQ(TimeDelta::FromMicroseconds(zero),
+            TimeDelta::FromMicroseconds(zero).magnitude());
+
+  const int64 one = 1;
+  const int64 negative_one = -1;
+  EXPECT_EQ(TimeDelta::FromMicroseconds(one),
+            TimeDelta::FromMicroseconds(one).magnitude());
+  EXPECT_EQ(TimeDelta::FromMicroseconds(one),
+            TimeDelta::FromMicroseconds(negative_one).magnitude());
+
+  const int64 max_int64_minus_one = std::numeric_limits<int64>::max() - 1;
+  const int64 min_int64_plus_two = std::numeric_limits<int64>::min() + 2;
+  EXPECT_EQ(TimeDelta::FromMicroseconds(max_int64_minus_one),
+            TimeDelta::FromMicroseconds(max_int64_minus_one).magnitude());
+  EXPECT_EQ(TimeDelta::FromMicroseconds(max_int64_minus_one),
+            TimeDelta::FromMicroseconds(min_int64_plus_two).magnitude());
+}
+
 TEST(TimeDeltaLogging, DCheckEqCompiles) {
   DCHECK_EQ(TimeDelta(), TimeDelta());
 }