Hook up PA_LOG() logs to chrome://proximity-auth WebUI.

components/proximity_auth/logging/log_buffer.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/log_buffer.h"
 
 #include "base/lazy_instance.h"
 
 namespace proximity_auth {
 
@@ skipping 19 matching lines @@
 }
 
 LogBuffer::~LogBuffer() {
 }
 
 // static
 LogBuffer* LogBuffer::GetInstance() {
   return &g_log_buffer.Get();
 }
 
+void LogBuffer::AddObserver(Observer* observer) {
+  observers_.AddObserver(observer);
+}
+
+void LogBuffer::RemoveObserver(Observer* observer) {
+  observers_.RemoveObserver(observer);
+}
+
 void LogBuffer::AddLogMessage(const LogMessage& log_message) {
   // Note: We may want to sort the messages by timestamp if there are cases
   // where logs are not added chronologically.
   log_messages_.push_back(log_message);
   if (log_messages_.size() > MaxBufferSize())
     log_messages_.pop_front();
+  FOR_EACH_OBSERVER(Observer, observers_, OnLogMessageAdded(log_message));
 }
 
 void LogBuffer::Clear() {
   log_messages_.clear();
+  FOR_EACH_OBSERVER(Observer, observers_, OnLogBufferCleared());
 }
 
 size_t LogBuffer::MaxBufferSize() const {
   return kMaxBufferSize;
 }
 
 }  // proximity_auth