Oilpan: Implement a GC to take a heap snapshot

Source/platform/heap/HeapTest.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 212 matching lines @@
 
 class TestGCScope {
 public:
     explicit TestGCScope(ThreadState::StackState state)
         : m_state(ThreadState::current())
         , m_safePointScope(state)
         , m_parkedAllThreads(false)
     {
         m_state->checkThread();
         if (LIKELY(ThreadState::stopThreads())) {
-            Heap::preGC();
+            Heap::preGC(ThreadState::GCWithSweep);
             m_parkedAllThreads = true;
         }
     }
 
     bool allThreadsParked() { return m_parkedAllThreads; }
 
     ~TestGCScope()
     {
         // Only cleanup if we parked all threads in which case the GC happened
         // and we need to resume the other threads.
@@ skipping 266 matching lines @@
                 for (int i = 0; i < numberOfAllocations; i++) {
                     wrapper = IntWrapper::create(0x0bbac0de);
                     if (!(i % 10)) {
                         globalPersistent = adoptPtr(new GlobalIntWrapperPersistent(IntWrapper::create(0x0ed0cabb)));
                     }
                     SafePointScope scope(ThreadState::NoHeapPointersOnStack);
                     Platform::current()->yieldCurrentThread();
                 }
 
                 if (gcCount < gcPerThread) {
+                    // Taking snapshot shouldn't have any bad side effect.
+                    Heap::collectGarbage(ThreadState::NoHeapPointersOnStack, ThreadState::TakeSnapshot, Heap::ForcedGC);
                     Heap::collectGarbage(ThreadState::NoHeapPointersOnStack, ThreadState::GCWithSweep, Heap::ForcedGC);
                     gcCount++;
                     atomicIncrement(&m_gcCount);
                 }
 
+                // Taking snapshot shouldn't have any bad side effect.
+                Heap::collectGarbage(ThreadState::NoHeapPointersOnStack, ThreadState::TakeSnapshot, Heap::ForcedGC);
                 Heap::collectGarbage(ThreadState::NoHeapPointersOnStack, ThreadState::GCWithSweep, Heap::ForcedGC);
                 EXPECT_EQ(wrapper->value(), 0x0bbac0de);
                 EXPECT_EQ((*globalPersistent)->value(), 0x0ed0cabb);
             }
             SafePointScope scope(ThreadState::NoHeapPointersOnStack);
             Platform::current()->yieldCurrentThread();
         }
         ThreadState::detach();
         atomicDecrement(&m_threadsToFinish);
     }
@@ skipping 5575 matching lines @@
 {
     Persistent<ClassWithMember> object = ClassWithMember::create();
     EXPECT_EQ(0, object->traceCount());
     TestMixinAllocatingObject* mixin = TestMixinAllocatingObject::create(object.get());
     EXPECT_TRUE(mixin);
     EXPECT_GT(object->traceCount(), 0);
     EXPECT_GT(mixin->traceCount(), 0);
 }
 
 } // namespace blink