Move timing files into base/time, install forwarding headers.

base/time/time.h

Index: base/time/time.h
diff --git a/base/time.h b/base/time/time.h
similarity index 99%
copy from base/time.h
copy to base/time/time.h
index e722122d2113d7adfcf054ba072825cf5f0cb01e..12995196a4ea6eb3234f4e9e5c220bf428517e73 100644
--- a/base/time.h
+++ b/base/time/time.h
@@ -20,8 +20,8 @@
 // These classes are represented as only a 64-bit value, so they can be
 // efficiently passed by value.
 
-#ifndef BASE_TIME_H_
-#define BASE_TIME_H_
+#ifndef BASE_TIME_TIME_H_
+#define BASE_TIME_TIME_H_
 
 #include <time.h>
 
@@ -648,4 +648,4 @@ inline TimeTicks TimeDelta::operator+(TimeTicks t) const {
 
 }  // namespace base
 
-#endif  // BASE_TIME_H_
+#endif  // BASE_TIME_TIME_H_