[Media Router] Clean up issues related code.

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"
 
 #include <algorithm>
 
 #include "content/public/browser/browser_thread.h"
 
 namespace media_router {
 
-IssueManager::IssueManager() {
+IssueManager::IssueManager() : top_issue_(nullptr) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 }
 
 IssueManager::~IssueManager() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 }
 
 void IssueManager::AddIssue(const Issue& issue) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-  for (const Issue& next_issue : issues_) {
-    if (next_issue.Equals(issue)) {
-      return;
-    }
-  }
+  if (ContainsValue(issues_, issue))
+    return;
+
   issues_.push_back(issue);
   MaybeUpdateTopIssue();
 }
 
 void IssueManager::ClearIssue(const Issue::Id& issue_id) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   issues_.erase(std::remove_if(issues_.begin(), issues_.end(),
                                [&issue_id](const Issue& issue) {
                                  return issue_id == issue.id();
                                }),
                 issues_.end());
   MaybeUpdateTopIssue();
 }
 
 size_t IssueManager::GetIssueCount() const {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   return issues_.size();
 }
 
 void IssueManager::ClearAllIssues() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   issues_.clear();
   MaybeUpdateTopIssue();
 }
 
 void IssueManager::ClearGlobalIssues() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   issues_.erase(
-      std::remove_if(issues_.begin(), issues_.end(), [](const Issue& issue) {
-        return issue.is_global();
-      }), issues_.end());
+      std::remove_if(issues_.begin(), issues_.end(),
+                     [](const Issue& issue) { return issue.IsGlobal(); }),
+      issues_.end());
   MaybeUpdateTopIssue();
 }
 
 void IssueManager::ClearIssuesWithRouteId(const MediaRoute::Id& route_id) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   issues_.erase(std::remove_if(issues_.begin(), issues_.end(),
                                [&route_id](const Issue& issue) {
                                  return route_id == issue.route_id();
                                }),
                 issues_.end());
   MaybeUpdateTopIssue();
 }
 
 void IssueManager::RegisterObserver(IssuesObserver* observer) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   DCHECK(observer);
   DCHECK(!issues_observers_.HasObserver(observer));
 
   issues_observers_.AddObserver(observer);
-  if (top_issue_id_.empty())
-    return;
-
-  // 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);
-    }
-  }
+  if (top_issue_)
+    observer->OnIssueUpdated(top_issue_);
 }
 
 void IssueManager::UnregisterObserver(IssuesObserver* observer) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   issues_observers_.RemoveObserver(observer);
 }
 
 void IssueManager::MaybeUpdateTopIssue() {
   const Issue* new_top_issue = nullptr;
+  if (!issues_.empty()) {
+    // Select the first blocking issue in the list of issues.
+    // If there are none, simply select the first issue in the list.
+    auto it =
+        std::find_if(issues_.begin(), issues_.end(),
+                     [](const Issue& issue) { return issue.IsBlocking(); });
+    if (it == issues_.end())
+      it = issues_.begin();
 
-  if (issues_.empty()) {
+    new_top_issue = &*it;
+  }
+  // If we've found a new top issue, then report it via the observer.
+  if (new_top_issue != top_issue_) {
+    top_issue_ = new_top_issue;
     FOR_EACH_OBSERVER(IssuesObserver, issues_observers_,
-                      OnIssueUpdated(new_top_issue));
-    return;
-  }
-
-  // Select the first blocking issue in the list of issues.
-  // If there are none, simply select the first issue in the list.
-  new_top_issue = &(issues_.front());
-  for (const auto& issue : issues_) {
-    // The first blocking issue is of higher priority than the first issue.
-    if (issue.is_blocking()) {
-      new_top_issue = &issue;
-      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));
+                      OnIssueUpdated(top_issue_));
   }
 }
 
 }  // namespace media_router