Reland r187230: Implement the Stream registry in content

content/browser/streams/stream_context.cc

+// Copyright (c) 2013 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 "content/browser/streams/stream_context.h"
+
+#include "base/bind.h"
+#include "content/browser/streams/stream_registry.h"
+#include "content/public/browser/browser_context.h"
+
+using base::UserDataAdapter;
+
+namespace {
+const char* kStreamContextKeyName = "content_stream_context";
+}
+
+namespace content {
+
+StreamContext::StreamContext() {}
+
+StreamContext* StreamContext::GetFor(BrowserContext* context) {
+  if (!context->GetUserData(kStreamContextKeyName)) {
+    scoped_refptr<StreamContext> stream = new StreamContext();
+    context->SetUserData(kStreamContextKeyName,
+                         new UserDataAdapter<StreamContext>(stream));
+    // Check first to avoid memory leak in unittests.
+    if (BrowserThread::IsMessageLoopValid(BrowserThread::IO)) {
+      BrowserThread::PostTask(
+          BrowserThread::IO, FROM_HERE,
+          base::Bind(&StreamContext::InitializeOnIOThread, stream));
+    }
+  }
+
+  return UserDataAdapter<StreamContext>::Get(context, kStreamContextKeyName);
+}
+
+void StreamContext::InitializeOnIOThread() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  registry_.reset(new StreamRegistry());
+}
+
+StreamContext::~StreamContext() {}
+
+void StreamContext::DeleteOnCorrectThread() const {
+  // In many tests, there isn't a valid IO thread.  In that case, just delete on
+  // the current thread.
+  // TODO(zork): Remove this custom deleter, and fix the leaks in all the
+  // tests.
+  if (BrowserThread::IsMessageLoopValid(BrowserThread::IO) &&
+      !BrowserThread::CurrentlyOn(BrowserThread::IO)) {
+    BrowserThread::DeleteSoon(BrowserThread::IO, FROM_HERE, this);
+    return;
+  }
+  delete this;
+}
+
+}  // namespace content