headless: Initial headless embedder API implementation

headless/lib/browser/headless_browser_impl.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 "headless/lib/browser/headless_browser_impl.h"
+
+#include "base/thread_task_runner_handle.h"
+#include "content/public/app/content_main.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/web_contents.h"
+#include "headless/lib/browser/headless_browser_context.h"
+#include "headless/lib/browser/headless_browser_main_parts.h"
+#include "headless/lib/browser/headless_web_contents_impl.h"
+#include "headless/lib/headless_content_main_delegate.h"
+#include "ui/aura/env.h"
+#include "ui/aura/window_tree_host.h"
+#include "ui/gfx/geometry/size.h"
+
+namespace headless {
+
+HeadlessBrowserImpl::HeadlessBrowserImpl(
+    const StartCallback& on_start_callback,
+    const HeadlessBrowser::Options& options)

[Ryan Sleevi, 2016/02/22 22:01:21]

STYLE: Your .cc order should match your .h order - this should appear at the end
of the file.

[Sami, 2016/02/23 20:19:07]

Done.

+    : on_start_callback_(on_start_callback),
+      options_(options),
+      browser_main_parts_(nullptr) {}
+
+HeadlessBrowserImpl::~HeadlessBrowserImpl() {}
+
+scoped_ptr<HeadlessWebContents> HeadlessBrowserImpl::CreateWebContents(
+    const gfx::Size& size) {
+  DCHECK(BrowserMainThread()->BelongsToCurrentThread());
+  return make_scoped_ptr(new HeadlessWebContentsImpl(
+      browser_context(), window_tree_host_->window(), size));
+}
+
+scoped_refptr<base::SingleThreadTaskRunner>
+HeadlessBrowserImpl::BrowserMainThread() const {
+  return content::BrowserThread::GetMessageLoopProxyForThread(
+      content::BrowserThread::UI);
+}
+
+void HeadlessBrowserImpl::Stop() {
+  DCHECK(BrowserMainThread()->BelongsToCurrentThread());
+  BrowserMainThread()->PostTask(FROM_HERE,
+                                base::MessageLoop::QuitWhenIdleClosure());

[Ryan Sleevi, 2016/02/22 22:01:21]

Are you sure this is the right place to put this? The runloop here is
externalized in this case - isn't that the code that should be invoking
shutdown? Do you need to propogate any other work to quiesce to an idle state? 

[Sami, 2016/02/23 20:19:08]

The RunLoop is actually still owned by content::BrowserMainRunner -- it's just
that the embedder will be able to override the message pump. Based on that it
seems appropriate to quit the run loop here.

+}
+
+HeadlessBrowserContext* HeadlessBrowserImpl::browser_context() const {
+  DCHECK(BrowserMainThread()->BelongsToCurrentThread());
+  DCHECK(browser_main_parts());
+  return browser_main_parts()->browser_context();
+}
+
+HeadlessBrowserMainParts* HeadlessBrowserImpl::browser_main_parts() const {
+  DCHECK(BrowserMainThread()->BelongsToCurrentThread());
+  return browser_main_parts_;
+}
+
+void HeadlessBrowserImpl::set_browser_main_parts(
+    HeadlessBrowserMainParts* browser_main_parts) {
+  DCHECK(!browser_main_parts_);
+  browser_main_parts_ = browser_main_parts;
+}
+
+void HeadlessBrowserImpl::RunOnStartCallback() {
+  DCHECK(aura::Env::GetInstance());
+  window_tree_host_.reset(aura::WindowTreeHost::Create(gfx::Rect()));
+  window_tree_host_->InitHost();
+
+  if (!on_start_callback_.is_null()) {
+    on_start_callback_.Run(this);
+    on_start_callback_ = StartCallback();
+  }

[Ryan Sleevi, 2016/02/22 22:01:21]

DESIGN: This is a confusing API contract that you allow is_null() callbacks. Is
this really what you want? Usually checking .is_null() is an anti-pattern for
callback use, and so it helps to understand.

[Sami, 2016/02/23 20:19:07]

Good point. This was here only for testing -- I've added a valid callback to the
test framework instead.

+}
+
+int HeadlessBrowser::Run(const Options& options,
+                         const StartCallback& on_browser_start_callback) {
+  scoped_ptr<HeadlessBrowserImpl> browser(
+      new HeadlessBrowserImpl(on_browser_start_callback, options));
+
+  // TODO(skyostil): Implement custom message pumps.
+  DCHECK(!options.message_pump);
+
+  headless::HeadlessContentMainDelegate delegate(std::move(browser));
+  content::ContentMainParams params(&delegate);
+  params.argc = options.argc;
+  params.argv = options.argv;
+  return content::ContentMain(params);
+}
+
+}  // namespace headless