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

base/test/mock_log.h

 // 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.
 
 #ifndef BASE_TEST_MOCK_LOG_H_
 #define BASE_TEST_MOCK_LOG_H_
 
 #include <stddef.h>
 
+#include <memory>
 #include <string>
 
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/synchronization/lock.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 namespace base {
 namespace test {
 
+class MockLogMessageListener;
+
 // A MockLog object intercepts LOG() messages issued during its lifespan.  Using
 // this together with gMock, it's very easy to test how a piece of code calls
 // LOG().  The typical usage:
 //
 //   TEST(FooTest, LogsCorrectly) {
 //     MockLog log;
 //
 //     // We expect the WARNING "Something bad!" exactly twice.
 //     EXPECT_CALL(log, Log(WARNING, _, "Something bad!"))
 //         .Times(2);
@@ skipping 23 matching lines @@
   ~MockLog();
 
   // Starts log capturing if the object isn't already doing so.
   // Otherwise crashes.
   void StartCapturingLogs();
 
   // Stops log capturing if the object is capturing logs.  Otherwise crashes.
   void StopCapturingLogs();
 
   // Log method is invoked for every log message before it's sent to other log
-  // destinations (if any).  The method should return true to signal that it
-  // handled the message and the message should not be sent to other log
-  // destinations.
+  // destinations (if any).
   MOCK_METHOD5(Log,
-               bool(int severity,
+               void(int severity,
                     const char* file,
                     int line,
                     size_t message_start,
                     const std::string& str));
 
  private:
-  // The currently active mock log.
-  static MockLog* g_instance_;
-
-  // Lock protecting access to g_instance_.
-  static Lock g_lock;
-
-  // Static function which is set as the logging message handler.
-  // Called once for each message.
-  static bool LogMessageHandler(int severity,
-                                const char* file,
-                                int line,
-                                size_t message_start,
-                                const std::string& str);
+  std::unique_ptr<MockLogMessageListener> listener_;
 
   // True if this object is currently capturing logs.
   bool is_capturing_logs_;
 
-  // The previous handler to restore when the MockLog is destroyed.
-  logging::LogMessageHandlerFunction previous_handler_;
-
   DISALLOW_COPY_AND_ASSIGN(MockLog);
 };
 
 }  // namespace test
 }  // namespace base
 
 #endif  // BASE_TEST_MOCK_LOG_H_