Adding freelist statistics to blink gc dump provider.

Source/platform/heap/ThreadState.cpp

Index: Source/platform/heap/ThreadState.cpp
diff --git a/Source/platform/heap/ThreadState.cpp b/Source/platform/heap/ThreadState.cpp
index 106c1c799bf7e811ad60b8e75f08e6a7595ae6a6..4cfc974c5ff7e034bebc0f62884121dde973c3b1 100644
--- a/Source/platform/heap/ThreadState.cpp
+++ b/Source/platform/heap/ThreadState.cpp
@@ -959,11 +959,13 @@ void ThreadState::postGC(GCType gcType)
     } else if (gcType == GCWithoutSweep) {
         setGCState(LazySweepScheduled);
     } else {
-        takeSnapshot();
+        takeSnapshot(SnapshotType::HeapSnapshot);
 
         // This unmarks all marked objects and marks all unmarked objects dead.
         makeConsistentForMutator();
 
+        takeSnapshot(SnapshotType::FreelistSnapshot);

[haraken, 2015/06/24 05:55:06]

May I ask you one more favor? What happens if you take a snapshot of freelists
before taking a snapshot of the heap?

I mean, what happens if you call
m_heaps[HeapType##HeapIndex]->takeFreelistSnapshot() just before calling
m_heaps[HeapType##HeapIndex]->takeSnapshot()?

If it works, it would be better since it will capture the actual shape of the
freelists (instead of the rebuilt freelists after the snapshot GC).

+
         // Force setting NoGCScheduled to circumvent checkThread()
         // in setGCState().
         m_gcState = NoGCScheduled;
@@ -1373,7 +1375,7 @@ void ThreadState::promptlyFreed(size_t gcInfoIndex)
     m_likelyToBePromptlyFreed[entryIndex] += 3;
 }
 
-void ThreadState::takeSnapshot()
+void ThreadState::takeSnapshot(SnapshotType type)
 {
     ASSERT(isInGC());
 
@@ -1383,7 +1385,16 @@ void ThreadState::takeSnapshot()
         numberOfHeapsReported++;                                                                               \
         String allocatorBaseName;                                                                              \
         allocatorBaseName = String::format("blink_gc/thread_%lu/heaps/" #HeapType, (unsigned long)(m_thread)); \
-        m_heaps[HeapType##HeapIndex]->takeSnapshot(allocatorBaseName);                                         \
+        switch (type) {                                                                                        \
+        case SnapshotType::HeapSnapshot:                                                                       \
+            m_heaps[HeapType##HeapIndex]->takeSnapshot(allocatorBaseName);                                     \
+            break;                                                                                             \
+        case SnapshotType::FreelistSnapshot:                                                                   \
+            m_heaps[HeapType##HeapIndex]->takeFreelistSnapshot(allocatorBaseName);                             \
+            break;                                                                                             \
+        default:                                                                                               \
+            ASSERT_NOT_REACHED();                                                                              \
+        }                                                                                                      \
     }
 
     SNAPSHOT_HEAP(NormalPage1);