Add TabManager class, relocate Tab to common/.

blimp/engine/common/tab_manager.cc

Index: blimp/engine/common/tab_manager.cc
diff --git a/blimp/engine/common/tab_manager.cc b/blimp/engine/common/tab_manager.cc
new file mode 100644
index 0000000000000000000000000000000000000000..97fa3e00566113dd994b3a3133c2eb1ac58074e9
--- /dev/null
+++ b/blimp/engine/common/tab_manager.cc
@@ -0,0 +1,59 @@
+// Copyright 2016 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 "blimp/engine/common/tab_manager.h"
+
+#include <utility>
+
+#include "base/macros.h"
+#include "base/stl_util.h"
+#include "blimp/engine/common/tab.h"
+
+namespace blimp {
+namespace engine {
+
+TabManager::TabManager() {}
+
+TabManager::~TabManager() {}
+
+void TabManager::Add(std::unique_ptr<Tab> tab) {
+  DCHECK(tab);
+  DCHECK(!ContainsKey(tabs_, tab->id()));
+
+  tabs_by_webcontents_[tab->web_contents()] = tab.get();
+  tabs_[tab->id()] = std::move(tab);
+}
+
+void TabManager::Remove(Tab* tab) {
+  DCHECK(tab);
+
+  if (!ContainsKey(tabs_, tab->id())) {
+    return;
+  }
+  tabs_by_webcontents_.erase(tabs_[tab->id()]->web_contents());
+  tabs_.erase(tab->id());
+}
+
+void TabManager::Clear() {
+  tabs_.clear();
+  tabs_by_webcontents_.clear();
+}
+
+Tab* TabManager::FindTabById(int tab_id) const {
+  return (tabs_.find(tab_id) != tabs_.end()) ? tabs_.find(tab_id)->second.get()
+                                             : nullptr;
+}
+
+Tab* TabManager::FindTabByWebContents(content::WebContents* contents) const {
+  return (tabs_by_webcontents_.find(contents) != tabs_by_webcontents_.end())
+             ? tabs_by_webcontents_.find(contents)->second
+             : nullptr;
+}
+
+Tab* TabManager::GetOnlyTab() const {
+  return (tabs_.size() == 1 ? tabs_.begin()->second.get() : nullptr);
+}
+
+}  // namespace engine
+}  // namespace blimp