[heap] Reland: Take page lock when scavenging old to new references in Scavenger.

src/heap/spaces.h

Index: src/heap/spaces.h
diff --git a/src/heap/spaces.h b/src/heap/spaces.h
index 1cd7257677223484eae6dd7f43322f97f01a1f12..ff27d09c3aac38b2eedf1bda874fa3d3fc1ebcde 100644
--- a/src/heap/spaces.h
+++ b/src/heap/spaces.h
@@ -344,7 +344,7 @@ class MemoryChunk {
       + kPointerSize * NUMBER_OF_REMEMBERED_SET_TYPES  // TypedSlotSet* array
       + kPointerSize                                   // SkipList* skip_list_
       + kPointerSize    // AtomicValue high_water_mark_
-      + kPointerSize    // base::Mutex* mutex_
+      + kPointerSize    // base::RecursiveMutex* mutex_
       + kPointerSize    // base::AtomicWord concurrent_sweeping_
       + 2 * kSizetSize  // AtomicNumber free-list statistics
       + kPointerSize    // AtomicValue next_chunk_
@@ -404,7 +404,7 @@ class MemoryChunk {
     return reinterpret_cast<Address>(const_cast<MemoryChunk*>(this));
   }
 
-  base::Mutex* mutex() { return mutex_; }
+  base::RecursiveMutex* mutex() { return mutex_; }
 
   bool Contains(Address addr) {
     return addr >= area_start() && addr < area_end();
@@ -613,7 +613,7 @@ class MemoryChunk {
   // count highest number of bytes ever allocated on the page.
   base::AtomicValue<intptr_t> high_water_mark_;
 
-  base::Mutex* mutex_;
+  base::RecursiveMutex* mutex_;
 
   base::AtomicValue<ConcurrentSweepingState> concurrent_sweeping_;