Revert "Change the history state throttle interval from 60 to 120 Hz."

This reverts commit 8e4127dd.

Reason for revert: Part 1 of trying to revert the history throttling changes, to see if https://bugs.chromium.org/p/chromium/issues/detail?id=870861 improves.

Original change's description:
> Change the history state throttle interval from 60 to 120 Hz.
> 
> This is a bit more lenient and may enable some callers, including a flaky test,
> to get (more of) what they need. The test's root problem seems to be data races
> (see issue 847326), however.
> 
> Bug: 870861
> Change-Id: I249e9f06fa9a9a9f3b74e53cf2ef3f34b0c2371c
> Reviewed-on: https://chromium-review.googlesource.com/1171825
> Reviewed-by: Daniel Cheng <dcheng@chromium.org>
> Commit-Queue: Chris Palmer <palmer@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#582415}

TBR=palmer@chromium.org,dcheng@chromium.org,kinuko@chromium.org

Change-Id: I9fb7b5b0f8ebff8b6d6c5a772745cfd2c10ef51a
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 870861
Reviewed-on: https://chromium-review.googlesource.com/1171708Reviewed-by: Peter Kasting <pkasting@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#582432}

third_party/blink/renderer/core/frame/history.cc

@@ -155,12 +155,11 @@ bool History::ShouldThrottleStateObjectChanges() {
 
   const auto now = TimeTicks::Now();
   const TimeDelta elapsed = now - state_flood_guard.last_token_grant;
-  static constexpr base::TimeDelta kTokenRefreshInterval =
-      base::TimeDelta::FromMilliseconds(8);
+  static constexpr base::TimeDelta kTimePerToken =
+      base::TimeDelta::FromMilliseconds(16);
   static constexpr int kMaxTokens = 50;
   // It is OK to truncate from int64_t to int here.
-  const int tokens_earned =
-      std::min<int>(elapsed / kTokenRefreshInterval, kMaxTokens);
+  const int tokens_earned = std::min<int>(elapsed / kTimePerToken, kMaxTokens);
 
   if (tokens_earned > 0) {
     state_flood_guard.tokens = tokens_earned - 1;  // One consumed immediately.