[fuchsia] Replace zx_clock_get() with zx_clock_get_new().

zx_clock_get() signature is being replaced to report errors.
As part of a soft transition, zx_clock_get_new() is introduced with
the final function signature.

Bug: chromium:963956
Change-Id: Ia6d0f4fc560bd9149683011099b064540b54edd6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1616545
Commit-Queue: Fabrice de Gans-Riberi <fdegans@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61591}

src/base/platform/platform-fuchsia.cc

@@ -150,7 +150,10 @@ void OS::SignalCodeMovingGC() {
 int OS::GetUserTime(uint32_t* secs, uint32_t* usecs) {
   const auto kNanosPerMicrosecond = 1000ULL;
   const auto kMicrosPerSecond = 1000000ULL;
-  const zx_time_t nanos_since_thread_started = zx_clock_get(ZX_CLOCK_THREAD);
+  zx_time_t nanos_since_thread_started;
+  zx_status_t status =
+      zx_clock_get_new(ZX_CLOCK_THREAD, &nanos_since_thread_started);
+  DCHECK_EQ(status, ZX_OK);
 
   // First convert to microseconds, rounding up.
   const uint64_t micros_since_thread_started =