- Address review comments from https://codereview.chromium.org/474913004/

runtime/vm/pages.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/pages.h"
 
 #include "platform/assert.h"
 #include "vm/compiler_stats.h"
 #include "vm/gc_marker.h"
 #include "vm/gc_sweeper.h"
@@ skipping 121 matching lines @@
                              FLAG_heap_growth_rate,
                              FLAG_heap_growth_time_ratio),
       gc_time_micros_(0),
       collections_(0) {
 }
 
 
 PageSpace::~PageSpace() {
   {
     MonitorLocker ml(tasks_lock());
-    ASSERT(tasks() == 0);
+    while (tasks() > 0) {
+      ml.Wait();
+    }
   }
   FreePages(pages_);
   FreePages(large_pages_);
   delete tasks_lock_;
 }
 
 
 intptr_t PageSpace::LargePageSizeInWordsFor(intptr_t size) {
   intptr_t page_size = Utils::RoundUp(size + HeapPage::ObjectStartOffset(),
                                       VirtualMemory::PageSize());
@@ skipping 362 matching lines @@
 }
 
 
 void PageSpace::MarkSweep(bool invoke_api_callbacks) {
   Isolate* isolate = heap_->isolate();
   ASSERT(isolate == Isolate::Current());
 
   // Wait for pending tasks to complete and then account for the driver task.
   {
     MonitorLocker locker(tasks_lock());
-    while (tasks() != 0) {
+    while (tasks() > 0) {
       locker.Wait();
     }
     set_tasks(1);
   }
 
   NoHandleScope no_handles(isolate);
 
   if (FLAG_print_free_list_before_gc) {
     OS::Print("Data Freelist (before GC):\n");
     freelist_[HeapPage::kData].Print();
@@ skipping 93 matching lines @@
   }
 
   if (FLAG_verify_after_gc) {
     OS::PrintErr("Verifying after MarkSweep...");
     heap_->Verify();
     OS::PrintErr(" done.\n");
   }
 
   // Done, reset the task count.
   {
-    MonitorLocker locker(tasks_lock());
+    MonitorLocker ml(tasks_lock());
     ASSERT(tasks() == 1);
     set_tasks(tasks() - 1);
+    ml.Notify();
   }
 }
 
 
 PageSpaceController::PageSpaceController(Heap* heap,
                                          int heap_growth_ratio,
                                          int heap_growth_max,
                                          int garbage_collection_time_ratio)
     : heap_(heap),
       is_enabled_(false),
@@ skipping 105 matching lines @@
     return 0;
   } else {
     ASSERT(total_time >= gc_time);
     int result= static_cast<int>((static_cast<double>(gc_time) /
                              static_cast<double>(total_time)) * 100);
     return result;
   }
 }
 
 }  // namespace dart