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

base/test/mock_log.h

Index: base/test/mock_log.h
diff --git a/base/test/mock_log.h b/base/test/mock_log.h
index cda2fcd6259cbf080ba1bdc0c4195c00a12d69be..adac25e494d9d0e34ab16c2f9af305911a08f42d 100644
--- a/base/test/mock_log.h
+++ b/base/test/mock_log.h
@@ -7,6 +7,7 @@
 
 #include <stddef.h>
 
+#include <memory>
 #include <string>
 
 #include "base/logging.h"
@@ -17,6 +18,8 @@
 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:
@@ -60,37 +63,20 @@ class MockLog {
   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);
 };