[tracing] use SHA1 instead of base::Hash for memory dump GUIDs

base/trace_event/memory_allocator_dump_guid.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/memory_allocator_dump_guid.h"
 
 #include "base/format_macros.h"
-#include "base/hash.h"
+#include "base/sha1.h"
 #include "base/strings/stringprintf.h"
 
 namespace base {
 namespace trace_event {
 
+namespace {
+uint64 HashString(const std::string& str) {
+  uint64 hash[(kSHA1Length + sizeof(uint64) - 1) / sizeof(uint64)] = { 0 };
+  SHA1HashBytes(reinterpret_cast<const unsigned char*>(str.data()), str.size(),
+                reinterpret_cast<unsigned char*>(hash));
+  return hash[0];
+}
+}  // namespace
+
 MemoryAllocatorDumpGuid::MemoryAllocatorDumpGuid(uint64 guid) : guid_(guid) {
 }
 
 MemoryAllocatorDumpGuid::MemoryAllocatorDumpGuid()
     : MemoryAllocatorDumpGuid(0u) {
 }
 
 MemoryAllocatorDumpGuid::MemoryAllocatorDumpGuid(const std::string& guid_str)
-    : MemoryAllocatorDumpGuid(Hash(guid_str)) {
+    : MemoryAllocatorDumpGuid(HashString(guid_str)) {
 }
 
 std::string MemoryAllocatorDumpGuid::ToString() const {
   return StringPrintf("%" PRIx64, guid_);
 }
 
 }  // namespace trace_event
 }  // namespace base