Allow multiple logging::LogMessage{Handler,Listener}s

components/proximity_auth/logging/logging_unittest.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 "components/proximity_auth/logging/logging.h"
 
 #include <stddef.h>
 
 #include "base/lazy_instance.h"
+#include "base/memory/ptr_util.h"
 #include "base/numerics/safe_conversions.h"
 #include "base/strings/string_number_conversions.h"
 #include "components/proximity_auth/logging/log_buffer.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace proximity_auth {
 
 namespace {
 
 const char kLog1[] = "Mahogony destined to make a sturdy table";
 const char kLog2[] = "Construction grade cedar";
 const char kLog3[] = "Pine infested by hungry beetles";
 
 // Called for every log message added to the standard logging system. The new
 // log is saved in |g_standard_logs| and consumed so it does not flood stdout.
 base::LazyInstance<std::vector<std::string>> g_standard_logs =
     LAZY_INSTANCE_INITIALIZER;
-bool HandleStandardLogMessage(int severity,
-                              const char* file,
-                              int line,
-                              size_t message_start,
-                              const std::string& str) {
-  g_standard_logs.Get().push_back(str);
-  return true;
-}
+class StandardLogMessageHandler : logging::LogMessageHandler {
+  bool OnMessage(int severity,
+                 const char* file,
+                 int line,
+                 size_t message_start,
+                 const std::string& str) override {
+    g_standard_logs.Get().push_back(str);
+    return true;
+  }
+};
 
 }  // namespace
 
 class ProximityAuthLoggingTest : public testing::Test {
  public:
-  ProximityAuthLoggingTest() : previous_handler_(NULL) {}
-
   void SetUp() override {
     LogBuffer::GetInstance()->Clear();
     g_standard_logs.Get().clear();
 
-    previous_handler_ = logging::GetLogMessageHandler();
-    logging::SetLogMessageHandler(&HandleStandardLogMessage);
+    log_handler_ = base::MakeUnique<StandardLogMessageHandler>();
   }
 
-  void TearDown() override { logging::SetLogMessageHandler(previous_handler_); }
+  void TearDown() override { log_handler_.reset(); }
 
  private:
-  logging::LogMessageHandlerFunction previous_handler_;
+  std::unique_ptr<StandardLogMessageHandler> log_handler_;
 };
 
 TEST_F(ProximityAuthLoggingTest, LogsSavedToBuffer) {
   int base_line_number = __LINE__;
   PA_LOG(INFO) << kLog1;
   PA_LOG(WARNING) << kLog2;
   PA_LOG(ERROR) << kLog3;
 
   auto* logs = LogBuffer::GetInstance()->logs();
   ASSERT_EQ(3u, logs->size());
@@ skipping 46 matching lines @@
   PA_LOG(WARNING) << kLog2;
   PA_LOG(ERROR) << kLog3;
 
   ASSERT_EQ(3u, g_standard_logs.Get().size());
   EXPECT_NE(std::string::npos, g_standard_logs.Get()[0].find(kLog1));
   EXPECT_NE(std::string::npos, g_standard_logs.Get()[1].find(kLog2));
   EXPECT_NE(std::string::npos, g_standard_logs.Get()[2].find(kLog3));
 }
 
 }  // namespace proximity_auth