Update from https://crrev.com/333737

base/trace_event/winheap_dump_provider_win.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/trace_event/winheap_dump_provider_win.h"
 
 #include <windows.h>
 
 #include "base/trace_event/process_memory_dump.h"
+#include "base/win/windows_version.h"
 
 namespace base {
 namespace trace_event {
 
 namespace {
 
 // Report a heap dump to a process memory dump. The |heap_info| structure
 // contains the information about this heap, and |dump_absolute_name| will be
 // used to represent it in the report.
-bool ReportHeapDump(ProcessMemoryDump* pmd,
+void ReportHeapDump(ProcessMemoryDump* pmd,
                     const WinHeapInfo& heap_info,
                     const std::string& dump_absolute_name) {
-  MemoryAllocatorDump* dump = pmd->CreateAllocatorDump(dump_absolute_name);
-  if (!dump)
-    return false;
-  dump->AddScalar(MemoryAllocatorDump::kNameOuterSize,
-                  MemoryAllocatorDump::kUnitsBytes, heap_info.committed_size);
-  dump->AddScalar(MemoryAllocatorDump::kNameInnerSize,
-                  MemoryAllocatorDump::kUnitsBytes, heap_info.allocated_size);
-  dump->AddScalar(MemoryAllocatorDump::kNameObjectsCount,
-                  MemoryAllocatorDump::kUnitsObjects, heap_info.block_count);
-  return true;
+  MemoryAllocatorDump* outer_dump =
+      pmd->CreateAllocatorDump(dump_absolute_name);
+  outer_dump->AddScalar(MemoryAllocatorDump::kNameSize,
+                        MemoryAllocatorDump::kUnitsBytes,
+                        heap_info.committed_size);
+
+  MemoryAllocatorDump* inner_dump =
+      pmd->CreateAllocatorDump(dump_absolute_name + "/allocated_objects");
+  inner_dump->AddScalar(MemoryAllocatorDump::kNameSize,
+                        MemoryAllocatorDump::kUnitsBytes,
+                        heap_info.allocated_size);
+  inner_dump->AddScalar(MemoryAllocatorDump::kNameObjectsCount,
+                        MemoryAllocatorDump::kUnitsObjects,
+                        heap_info.block_count);
 }
 
 }  // namespace
 
 WinHeapDumpProvider* WinHeapDumpProvider::GetInstance() {
   return Singleton<WinHeapDumpProvider,
                    LeakySingletonTraits<WinHeapDumpProvider>>::get();
 }
 
 bool WinHeapDumpProvider::OnMemoryDump(ProcessMemoryDump* pmd) {
+  // This method might be flaky for 2 reasons:
+  //   - GetProcessHeaps is racy by design. It returns a snapshot of the
+  //     available heaps, but there's no guarantee that that snapshot remains
+  //     valid. If a heap disappears between GetProcessHeaps() and HeapWalk()
+  //     then chaos should be assumed. This flakyness is acceptable for tracing.
+  //   - The MSDN page for HeapLock says: "If the HeapLock function is called on
+  //     a heap created with the HEAP_NO_SERIALIZATION flag, the results are
+  //     undefined.". This is a problem on Windows XP where some system DLLs are
+  //     known for creating heaps with this particular flag. For this reason
+  //     this function should be disabled on XP.
+  //
+  // See https://crbug.com/487291 for more details about this.
+  if (base::win::GetVersion() < base::win::VERSION_VISTA)
+    return false;
+
   // Retrieves the number of heaps in the current process.
   DWORD number_of_heaps = ::GetProcessHeaps(0, NULL);
   WinHeapInfo all_heap_info = {0};
 
   // Try to retrieve a handle to all the heaps owned by this process. Returns
   // false if the number of heaps has changed.
   //
   // This is inherently racy as is, but it's not something that we observe a lot
   // in Chrome, the heaps tend to be created at startup only.
   scoped_ptr<HANDLE[]> all_heaps(new HANDLE[number_of_heaps]);
   if (::GetProcessHeaps(number_of_heaps, all_heaps.get()) != number_of_heaps)
     return false;
 
   // Skip the pointer to the heap array to avoid accounting the memory used by
   // this dump provider.
   std::set<void*> block_to_skip;
   block_to_skip.insert(all_heaps.get());
 
   // Retrieves some metrics about each heap.
   for (size_t i = 0; i < number_of_heaps; ++i) {
     WinHeapInfo heap_info = {0};
     heap_info.heap_id = all_heaps[i];
     GetHeapInformation(&heap_info, block_to_skip);
 
     all_heap_info.allocated_size += heap_info.allocated_size;
     all_heap_info.committed_size += heap_info.committed_size;
     all_heap_info.block_count += heap_info.block_count;
   }
   // Report the heap dump.
-  if (!ReportHeapDump(pmd, all_heap_info, "winheap"))
-    return false;
-
+  ReportHeapDump(pmd, all_heap_info, "winheap");
   return true;
 }
 
 bool WinHeapDumpProvider::GetHeapInformation(
     WinHeapInfo* heap_info,
     const std::set<void*>& block_to_skip) {
   CHECK(::HeapLock(heap_info->heap_id) == TRUE);
   PROCESS_HEAP_ENTRY heap_entry;
   heap_entry.lpData = nullptr;
   // Walk over all the entries in this heap.
   while (::HeapWalk(heap_info->heap_id, &heap_entry) != FALSE) {
     if (block_to_skip.count(heap_entry.lpData) == 1)
       continue;
     if ((heap_entry.wFlags & PROCESS_HEAP_ENTRY_BUSY) != 0) {
       heap_info->allocated_size += heap_entry.cbData;
       heap_info->block_count++;
     } else if ((heap_entry.wFlags & PROCESS_HEAP_REGION) != 0) {
       heap_info->committed_size += heap_entry.Region.dwCommittedSize;
     }
   }
   CHECK(::HeapUnlock(heap_info->heap_id) == TRUE);
   return true;
 }
 
 }  // namespace trace_event
 }  // namespace base