PartitionAllocMemoryDumpProvider can directly inherit from MemoryDumpProvider

base/trace_event/process_memory_dump.h

Index: base/trace_event/process_memory_dump.h
diff --git a/base/trace_event/process_memory_dump.h b/base/trace_event/process_memory_dump.h
index 5ac14fea939a53be452481cca2ab90ea50ac79cb..51e4b5f5150a00f9fd563f8bfe6a3c827db2e3a7 100644
--- a/base/trace_event/process_memory_dump.h
+++ b/base/trace_event/process_memory_dump.h
@@ -119,9 +119,18 @@ class BASE_EXPORT ProcessMemoryDump {
   // Adds a heap dump for the allocator with |absolute_name|. The |TracedValue|
   // must have the correct format. |trace_event::HeapDumper| will generate such
   // a value from a |trace_event::AllocationRegister|.
+  // TODO(bashi): Remove this when WebMemoryDumpProvider is gone.
+  // http://crbug.com/605822
   void AddHeapDump(const std::string& absolute_name,
                    std::unique_ptr<TracedValue> heap_dump);
 
+  // Dumps heap usage with |allocator_name|.
+  void DumpHeapUsage(const base::hash_map<base::trace_event::AllocationContext,
+                                          base::trace_event::AllocationMetrics>&
+                         metrics_by_context,
+                     base::trace_event::TraceEventMemoryOverhead& overhead,
+                     const char* allocator_name);
+
   // Adds an ownership relationship between two MemoryAllocatorDump(s) with the
   // semantics: |source| owns |target|, and has the effect of attributing
   // the memory usage of |target| to |source|. |importance| is optional and