Update from https://crrev.com/327068

base/trace_event/memory_dump_provider.h

Index: base/trace_event/memory_dump_provider.h
diff --git a/base/trace_event/memory_dump_provider.h b/base/trace_event/memory_dump_provider.h
index 5cc3a6ee66c1d276a2a43dc7c722968417d7d2ef..9ec7ad92496c62c4c437968cc26659e35e935577 100644
--- a/base/trace_event/memory_dump_provider.h
+++ b/base/trace_event/memory_dump_provider.h
@@ -6,9 +6,13 @@
 #define BASE_TRACE_EVENT_MEMORY_DUMP_PROVIDER_H_
 
 #include "base/base_export.h"
-#include "base/trace_event/memory_allocator_attributes.h"
+#include "base/memory/ref_counted.h"
+#include "base/trace_event/memory_allocator_attributes_type_info.h"
 
 namespace base {
+
+class SingleThreadTaskRunner;
+
 namespace trace_event {
 
 class ProcessMemoryDump;
@@ -16,27 +20,46 @@ class ProcessMemoryDump;
 // The contract interface that memory dump providers must implement.
 class BASE_EXPORT MemoryDumpProvider {
  public:
-  // Called by the MemoryDumpManager when generating dump points.
+  // Called by the MemoryDumpManager when generating memory dumps.
   // Returns: true if the |pmd| was successfully populated, false otherwise.
   virtual bool DumpInto(ProcessMemoryDump* pmd) = 0;
 
   virtual const char* GetFriendlyName() const = 0;
 
-  const MemoryAllocatorDeclaredAttributes& allocator_attributes() const {
-    return allocator_attributes_;
+  const MemoryAllocatorAttributesTypeInfo& allocator_attributes_type_info()
+      const {
+    return allocator_attributes_type_info_;
+  }
+
+  // The dump provider can specify an optional thread affinity (in its
+  // base constructor call). If |task_runner| is non empty, all the calls to
+  // DumpInto are guaranteed to be posted to that TaskRunner.
+  const scoped_refptr<SingleThreadTaskRunner>& task_runner() const {
+    return task_runner_;
   }
 
  protected:
+  // Default ctor: the MDP is not bound to any thread (must be a singleton).
   MemoryDumpProvider();
+
+  // Use this ctor to ensure that DumpInto() is called always on the same thread
+  // specified by |task_runner|.
+  explicit MemoryDumpProvider(
+      const scoped_refptr<SingleThreadTaskRunner>& task_runner);
+
   virtual ~MemoryDumpProvider();
 
-  void DeclareAllocatorAttribute(const MemoryAllocatorDeclaredAttribute& attr);
+  void DeclareAllocatorAttribute(const std::string& allocator_name,
+                                 const std::string& attribute_name,
+                                 const std::string& attribute_type);
 
  private:
-  // The map (attribute name -> type) that specifies the semantic of the
-  // extra attributes that the MemoryAllocatorDump(s) produced by this
-  // MemoryDumpProvider will have.
-  MemoryAllocatorDeclaredAttributes allocator_attributes_;
+  // A map of attributes types (declared through DeclareAllocatorAttribute())
+  // emitted by this allocator dumper.
+  MemoryAllocatorAttributesTypeInfo allocator_attributes_type_info_;
+
+  // (Optional) TaskRunner on which the DumpInfo call should be posted.
+  scoped_refptr<SingleThreadTaskRunner> task_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(MemoryDumpProvider);
 };