Upstream the Media Router's Issue class.

chrome/browser/media/router/issue_manager.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 "chrome/browser/media/router/issue_manager.h"
+
+namespace media_router {
+
+IssueManager::IssueManager() {
+}
+
+IssueManager::~IssueManager() {
+}
+
+void IssueManager::AddIssue(const Issue& issue) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  for (const Issue& next_issue : issues_) {
+    if (next_issue.Equals(issue)) {
+      return;
+    }
+  }
+  issues_.push_back(issue);
+  MaybeUpdateTopIssue();
+}
+
+void IssueManager::ClearIssue(const Issue::IssueId& issue_id) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  for (auto it = issues_.begin(); it != issues_.end(); ++it) {

[DaleCurtis, 2015/05/04 20:03:29]

You can use std::remove_if() with a lambda for id equality to reduce this
substantially and avoid the RemoveIssue method below. 

[Kevin M, 2015/05/04 23:40:18]

Done.

+    if (it->id() == issue_id) {
+      RemoveIssue(it);
+      MaybeUpdateTopIssue();
+      return;
+    }
+  }
+}
+
+size_t IssueManager::GetIssueCount() const {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  return issues_.size();
+}
+
+void IssueManager::ClearAllIssues() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  issues_.clear();
+  MaybeUpdateTopIssue();
+}
+
+void IssueManager::ClearGlobalIssues() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  auto it = issues_.begin();
+  while (it != issues_.end()) {

[DaleCurtis, 2015/05/04 20:03:29]

Ditto.

[Kevin M, 2015/05/04 23:40:18]

Done.

+    if (it->is_global()) {
+      it = RemoveIssue(it);
+    } else {
+      it++;
+    }
+  }
+  MaybeUpdateTopIssue();
+}
+
+void IssueManager::ClearIssuesWithRouteId(const MediaRouteId& route_id) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  auto it = issues_.begin();
+  while (it != issues_.end()) {
+    if (it->route_id() == route_id) {

[DaleCurtis, 2015/05/04 20:03:29]

Ditto.

[Kevin M, 2015/05/04 23:40:18]

Done.

+      it = RemoveIssue(it);
+    } else {
+      it++;
+    }
+  }
+  MaybeUpdateTopIssue();
+}
+
+void IssueManager::RegisterObserver(IssuesObserver* observer) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(observer);
+  DCHECK(!issues_observers_.HasObserver(observer));
+
+  issues_observers_.AddObserver(observer);
+  if (!top_issue_id_.empty()) {
+    // Find the current top issue and report it to the observer.
+    for (const auto& next_issue : issues_) {
+      if (next_issue.id() == top_issue_id_) {
+        observer->OnIssueUpdated(&next_issue);
+      }
+    }
+  }
+}
+
+void IssueManager::UnregisterObserver(IssuesObserver* observer) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  issues_observers_.RemoveObserver(observer);
+}
+
+std::vector<Issue>::iterator IssueManager::RemoveIssue(
+    std::vector<Issue>::iterator issue_it) {
+  if (top_issue_id_ == issue_it->id()) {
+    top_issue_id_.clear();
+  }
+  return issues_.erase(issue_it);
+}
+
+void IssueManager::MaybeUpdateTopIssue() {
+  if (issues_.empty()) {
+    return;
+  }
+
+  // Select the first blocking issue in the list of issues.
+  // If there are none, simply select the first issue in the list.
+  Issue* new_top_issue = &(issues_.front());
+  for (auto it = issues_.begin(); it != issues_.end(); ++it) {
+    // The first blocking issue is of higher priority than the first issue.
+    if (it->is_blocking()) {
+      new_top_issue = &(*it);
+      break;
+    }
+  }
+
+  // If we've found a new top issue, then report it via the observer.
+  if (new_top_issue->id() != top_issue_id_) {
+    top_issue_id_ = new_top_issue->id();
+    FOR_EACH_OBSERVER(IssuesObserver, issues_observers_,
+                      OnIssueUpdated(new_top_issue));
+  }
+}
+
+}  // namespace media_router