Migrate TabControlFeature from 0.5 to 0.6

blimp/client/core/contents/blimp_contents_manager.cc

+// 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/client/core/contents/blimp_contents_manager.h"
+
+#include "base/bind.h"
+#include "base/memory/ptr_util.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "blimp/client/public/contents/blimp_contents_observer.h"
+
+namespace {
+const int kDummyTabId = 0;
+}
+
+namespace blimp {
+namespace client {
+
+class BlimpContentsManager::BlimpContentsDeletionObserver
+    : public BlimpContentsObserver {
+ public:
+  BlimpContentsDeletionObserver(BlimpContentsManager* blimp_contents_manager,
+                                BlimpContentsImpl* blimp_contents);
+
+  void OnContentsDestroyed() override;
+
+ private:
+  // The BlimpContentsManager containing this BlimpContentsDeletionObserver
+  BlimpContentsManager* blimp_contents_manager_;
+
+  DISALLOW_COPY_AND_ASSIGN(BlimpContentsDeletionObserver);
+};
+
+BlimpContentsManager::BlimpContentsDeletionObserver::
+    BlimpContentsDeletionObserver(BlimpContentsManager* blimp_contents_manager,
+                                  BlimpContentsImpl* blimp_contents)
+    : BlimpContentsObserver(blimp_contents),
+      blimp_contents_manager_(blimp_contents_manager) {}
+
+void BlimpContentsManager::BlimpContentsDeletionObserver::
+    OnContentsDestroyed() {
+  BlimpContents* contents = blimp_contents();
+  DCHECK(contents);
+  int id = static_cast<BlimpContentsImpl*>(contents)->id();
+  ClearBlimpContents();

[Menglin, 2016/08/05 23:37:15]

here it needs to first make sure it contents is not null. Then get its id, then
clear its contents. So I define a method just for contents_ = nullptr

+  DCHECK(base::ThreadTaskRunnerHandle::Get());
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE, base::Bind(&BlimpContentsManager::EraseObserverFromMap,
+                            blimp_contents_manager_->GetWeakPtr(), id));
+}
+
+BlimpContentsManager::BlimpContentsManager() : weak_ptr_factory_(this) {}
+
+BlimpContentsManager::~BlimpContentsManager() {}
+
+std::unique_ptr<BlimpContentsImpl> BlimpContentsManager::CreateBlimpContents() {
+  int id = CreateBlimpContentsId();
+  std::unique_ptr<BlimpContentsImpl> new_contents =
+      base::WrapUnique(new BlimpContentsImpl(id));

[nyquist, 2016/08/05 23:03:23]

Could you use base::MakeUnique here and on the line below?

[Menglin, 2016/08/06 00:57:00]

Done.

+  std::unique_ptr<BlimpContentsDeletionObserver> observer = base::WrapUnique(
+      new BlimpContentsDeletionObserver(this, new_contents.get()));
+  observer_map_.insert(
+      std::pair<int, std::unique_ptr<BlimpContentsDeletionObserver>>(
+          id, std::move(observer)));
+  return new_contents;
+}
+
+BlimpContentsImpl* BlimpContentsManager::GetBlimpContents(int id) {
+  if (observer_map_.find(id) != observer_map_.end()) {

[nyquist, 2016/08/05 23:03:23]

Could you just early out if this conditional fails? Then you don't have to
indent the rest.

[Menglin, 2016/08/06 00:57:00]

Done

+    BlimpContentsDeletionObserver* observer = observer_map_.at(id).get();
+    // If the BlimpContents that the observer tracks is empty, it means
+    // OnContentsDestroyed was called on this observer, but the task to erase
+    // the observer from the map hasn't been run.
+    if (observer->blimp_contents())
+      return static_cast<BlimpContentsImpl*>(observer->blimp_contents());
+  }
+  return nullptr;
+}
+
+int BlimpContentsManager::CreateBlimpContentsId() {
+  // TODO(mlliu): currently, Blimp only supports a single tab, so returning a
+  // dummy tab id. Need to return real case id when Blimp supports multiple
+  // tabs.
+  return kDummyTabId;
+}
+
+void BlimpContentsManager::EraseObserverFromMap(int id) {
+  observer_map_.erase(id);
+}
+
+base::WeakPtr<BlimpContentsManager> BlimpContentsManager::GetWeakPtr() {
+  return weak_ptr_factory_.GetWeakPtr();
+}
+
+}  // namespace client
+}  // namespace blimp