Replace uses of hash_map in //base

base/trace_event/process_memory_dump.cc

Index: base/trace_event/process_memory_dump.cc
diff --git a/base/trace_event/process_memory_dump.cc b/base/trace_event/process_memory_dump.cc
index 63d1340e42e3222c3ee99e92a7e676279cffb8a1..0c4c121f228e6d4af98fe358a0b559f1ef295117 100644
--- a/base/trace_event/process_memory_dump.cc
+++ b/base/trace_event/process_memory_dump.cc
@@ -239,8 +239,9 @@ MemoryAllocatorDump* ProcessMemoryDump::GetSharedGlobalAllocatorDump(
 }
 
 void ProcessMemoryDump::DumpHeapUsage(
-    const base::hash_map<base::trace_event::AllocationContext,
-        base::trace_event::AllocationMetrics>& metrics_by_context,
+    const std::unordered_map<base::trace_event::AllocationContext,
+                             base::trace_event::AllocationMetrics>&
+        metrics_by_context,
     base::trace_event::TraceEventMemoryOverhead& overhead,
     const char* allocator_name) {
   if (!metrics_by_context.empty()) {