Revert of Set lower allocation limit in idle notification only if no GC...

Revert of Set lower allocation limit in idle notification only if no GC happend recently. (patchset #2 id:20001 of https://codereview.chromium.org/1143113002/)

Reason for revert:
[Sheriff] MSAN not happy:
http://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20arm64%20-%20sim%20-%20MSAN/builds/2352

Original issue's description:
> Set lower allocation limit in idle notification only if no GC happend recently.
>
> BUG=475674
> LOG=n
>
> Committed: https://crrev.com/35e3489e8f70c7ad5973324ad3cfa4ab27059ab4
> Cr-Commit-Position: refs/heads/master@{#28506}

TBR=ulan@chromium.org,hpayer@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=475674

Review URL: https://codereview.chromium.org/1145113003

Cr-Commit-Position: refs/heads/master@{#28511}

src/heap/heap.cc

@@ -725,7 +725,6 @@ void Heap::GarbageCollectionEpilogue() {
   // Remember the last top pointer so that we can later find out
   // whether we allocated in new space since the last GC.
   new_space_top_after_last_gc_ = new_space()->top();
-  last_gc_time_ = MonotonicallyIncreasingTimeInMs();
 }
 
 
@@ -4613,8 +4612,6 @@ bool Heap::IdleNotification(double deadline_in_seconds) {
       static_cast<size_t>(idle_time_in_ms) >
       GCIdleTimeHandler::kMaxFrameRenderingIdleTime;
 
-  static const double kLastGCTimeTreshold = 1000;
-
   GCIdleTimeHandler::HeapState heap_state;
   heap_state.contexts_disposed = contexts_disposed_;
   heap_state.contexts_disposal_rate =
@@ -4623,8 +4620,7 @@ bool Heap::IdleNotification(double deadline_in_seconds) {
   heap_state.incremental_marking_stopped = incremental_marking()->IsStopped();
   // TODO(ulan): Start incremental marking only for large heaps.
   intptr_t limit = old_generation_allocation_limit_;
-  if (is_long_idle_notification &&
-      (start_ms - last_gc_time_ > kLastGCTimeTreshold)) {
+  if (is_long_idle_notification) {
     limit = idle_old_generation_allocation_limit_;
   }
 

src/heap/heap.h

@@ -2142,18 +2142,15 @@ class Heap {
   // Minimal interval between two subsequent collections.
   double min_in_mutator_;
 
-  // Cumulative GC time spent in marking.
+  // Cumulative GC time spent in marking
   double marking_time_;
 
-  // Cumulative GC time spent in sweeping.
+  // Cumulative GC time spent in sweeping
   double sweeping_time_;
 
-  // Last time an idle notification happened.
+  // Last time an idle notification happened
   double last_idle_notification_time_;
 
-  // Last time a garbage collection happened.
-  double last_gc_time_;
-
   MarkCompactCollector mark_compact_collector_;
 
   StoreBuffer store_buffer_;