Replace uses of hash_map in //base

base/trace_event/heap_profiler_heap_dump_writer_unittest.cc

Index: base/trace_event/heap_profiler_heap_dump_writer_unittest.cc
diff --git a/base/trace_event/heap_profiler_heap_dump_writer_unittest.cc b/base/trace_event/heap_profiler_heap_dump_writer_unittest.cc
index 800b6235ea6d1e2e648b27ebb843acd4d4e70548..b090eee0d8e00865fec3bc1ca0091b31a1e359ac 100644
--- a/base/trace_event/heap_profiler_heap_dump_writer_unittest.cc
+++ b/base/trace_event/heap_profiler_heap_dump_writer_unittest.cc
@@ -179,7 +179,7 @@ TEST(HeapDumpWriterTest, SizeAndCountAreHexadecimal) {
 }
 
 TEST(HeapDumpWriterTest, BacktraceTypeNameTable) {
-  hash_map<AllocationContext, AllocationMetrics> metrics_by_context;
+  std::unordered_map<AllocationContext, AllocationMetrics> metrics_by_context;
 
   AllocationContext ctx;
   ctx.backtrace.frames[0] = kBrowserMain;
@@ -274,7 +274,7 @@ TEST(HeapDumpWriterTest, BacktraceTypeNameTable) {
 }
 
 TEST(HeapDumpWriterTest, InsignificantValuesNotDumped) {
-  hash_map<AllocationContext, AllocationMetrics> metrics_by_context;
+  std::unordered_map<AllocationContext, AllocationMetrics> metrics_by_context;
 
   AllocationContext ctx;
   ctx.backtrace.frames[0] = kBrowserMain;