support multiple log message handlers in base/logging.h

chrome/browser/media/webrtc/webrtc_browsertest_base.cc

Index: chrome/browser/media/webrtc/webrtc_browsertest_base.cc
diff --git a/chrome/browser/media/webrtc/webrtc_browsertest_base.cc b/chrome/browser/media/webrtc/webrtc_browsertest_base.cc
index 107b49f612b8ff72ad093d6ca6a5dc834688434b..29d4ec9a8b9f1415da46023e661f996cbdc25ce7 100644
--- a/chrome/browser/media/webrtc/webrtc_browsertest_base.cc
+++ b/chrome/browser/media/webrtc/webrtc_browsertest_base.cc
@@ -68,11 +68,10 @@ base::LazyInstance<bool> hit_javascript_errors_ =
 // WebrtcTestBase-inheriting test cases do not run in parallel (if they did they
 // would race to look at the log, which is global to all tests).
 bool JavascriptErrorDetectingLogHandler(int severity,
-                                        const char* file,
+                                        const std::string& file,
                                         int line,
-                                        size_t message_start,
                                         const std::string& str) {
-  if (file == NULL || std::string("CONSOLE") != file)
+  if (std::string("CONSOLE") != file)
     return false;
 
   bool contains_uncaught = str.find("\"Uncaught ") != std::string::npos;
@@ -125,7 +124,7 @@ class PermissionRequestObserver : public PermissionRequestManager::Observer {
 WebRtcTestBase::WebRtcTestBase(): detect_errors_in_javascript_(false) {
   // The handler gets set for each test method, but that's fine since this
   // set operation is idempotent.
-  logging::SetLogMessageHandler(&JavascriptErrorDetectingLogHandler);
+  logging::AddLogMessageHandler(&JavascriptErrorDetectingLogHandler);
   hit_javascript_errors_.Get() = false;
 
   EnablePixelOutput();
@@ -137,6 +136,7 @@ WebRtcTestBase::~WebRtcTestBase() {
         << "Encountered javascript errors during test execution (Search "
         << "for Uncaught or ERROR:CONSOLE in the test output).";
   }
+  logging::RemoveLogMessageHandler(&JavascriptErrorDetectingLogHandler);
 }
 
 bool WebRtcTestBase::GetUserMediaAndAccept(