[tracing] Adding class-wise memory statistics to blink gc memory dumps

Source/platform/heap/BlinkGCMemoryDumpProvider.cpp

Index: Source/platform/heap/BlinkGCMemoryDumpProvider.cpp
diff --git a/Source/platform/heap/BlinkGCMemoryDumpProvider.cpp b/Source/platform/heap/BlinkGCMemoryDumpProvider.cpp
index fcdcff1e611b4bbd405e37c3ae0c001af8a6fc44..46a9b496ed24e931437ae562b5f685ca56c7b6bc 100644
--- a/Source/platform/heap/BlinkGCMemoryDumpProvider.cpp
+++ b/Source/platform/heap/BlinkGCMemoryDumpProvider.cpp
@@ -28,11 +28,13 @@ bool BlinkGCMemoryDumpProvider::onMemoryDump(blink::WebProcessMemoryDump* memory
 {
     Heap::collectGarbage(ThreadState::NoHeapPointersOnStack, ThreadState::TakeSnapshot, Heap::ForcedGC);
     String dumpName = String::format("blink_gc/thread_%lu", static_cast<unsigned long>(WTF::currentThread()));
-    WebMemoryAllocatorDump* allocatorDump = memoryDump->createMemoryAllocatorDump(dumpName);
+    WebMemoryAllocatorDump* allocatorDump = m_currentProcessMemoryDump->getMemoryAllocatorDump(dumpName);
+    if (!allocatorDump)
+        allocatorDump = m_currentProcessMemoryDump->createMemoryAllocatorDump(dumpName);
     allocatorDump->AddScalar("size", "bytes", Heap::allocatedSpace());
 
     dumpName.append("/allocated_objects");
-    WebMemoryAllocatorDump* objectsDump = memoryDump->createMemoryAllocatorDump(dumpName);
+    WebMemoryAllocatorDump* objectsDump = m_currentProcessMemoryDump->createMemoryAllocatorDump(dumpName);
     objectsDump->AddScalar("size", "bytes", Heap::allocatedObjectSize() + Heap::markedObjectSize());
     objectsDump->AddScalar("estimated_live_object_size", "bytes", Heap::estimatedLiveObjectSize());