headless: Initial headless embedder API implementation

headless/lib/headless_content_main_delegate.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/headless_content_main_delegate.h"
+
+#include "base/command_line.h"
+#include "base/path_service.h"
+#include "base/run_loop.h"
+#include "base/trace_event/trace_event.h"
+#include "content/public/browser/browser_main_runner.h"
+#include "content/public/common/content_switches.h"
+#include "headless/lib/browser/headless_browser_impl.h"
+#include "headless/lib/browser/headless_content_browser_client.h"
+#include "headless/lib/renderer/headless_content_renderer_client.h"
+#include "headless/lib/utility/headless_content_utility_client.h"
+#include "ui/base/resource/resource_bundle.h"
+#include "ui/ozone/public/ozone_switches.h"
+
+namespace headless {
+namespace {
+// Keep in sync with content/common/content_constants_internal.h.
+// TODO(skyostil): Add a tracing test for this.
+const int kTraceEventBrowserProcessSortIndex = -6;
+
+HeadlessContentMainDelegate* g_current_headless_content_main_delegate = nullptr;
+}  // namespace
+
+HeadlessContentMainDelegate::HeadlessContentMainDelegate(
+    scoped_ptr<HeadlessBrowserImpl> browser)
+    : content_client_(browser->options()), browser_(std::move(browser)) {
+  DCHECK(!g_current_headless_content_main_delegate);
+  g_current_headless_content_main_delegate = this;
+}
+
+HeadlessContentMainDelegate::~HeadlessContentMainDelegate() {
+  DCHECK(g_current_headless_content_main_delegate == this);
+  g_current_headless_content_main_delegate = nullptr;
+}
+
+bool HeadlessContentMainDelegate::BasicStartupComplete(int* exit_code) {
+  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
+
+  command_line->AppendSwitch(switches::kNoSandbox);
+  command_line->AppendSwitch(switches::kSingleProcess);
+
+  // The headless backend is automatically chosen for a headless build, but also
+  // adding it here allows us to run in a non-headless build too.
+  command_line->AppendSwitchASCII(switches::kOzonePlatform, "headless");
+
+  // TODO(skyostil): Investigate using Mesa/SwiftShader for output.
+  command_line->AppendSwitch(switches::kDisableGpu);
+
+  SetContentClient(&content_client_);
+  return false;
+}
+
+void HeadlessContentMainDelegate::PreSandboxStartup() {
+  InitializeResourceBundle();
+}
+
+int HeadlessContentMainDelegate::RunProcess(
+    const std::string& process_type,
+    const content::MainFunctionParams& main_function_params) {
+  if (!process_type.empty())
+    return -1;
+
+  base::trace_event::TraceLog::GetInstance()->SetProcessName("HeadlessBrowser");
+  base::trace_event::TraceLog::GetInstance()->SetProcessSortIndex(
+      kTraceEventBrowserProcessSortIndex);
+
+  scoped_ptr<content::BrowserMainRunner> browser_runner(
+      content::BrowserMainRunner::Create());
+
+  int exit_code = browser_runner->Initialize(main_function_params);
+  DCHECK_LT(exit_code, 0) << "content::BrowserMainRunner::Initialize failed in "
+                             "HeadlessContentMainDelegate::RunProcess";
+
+  browser_->RunOnStartCallback();
+  browser_runner->Run();
+  browser_.reset();
+  browser_runner->Shutdown();
+
+  // Return value >=0 here to disable calling content::BrowserMain.
+  return 0;
+}
+
+void HeadlessContentMainDelegate::ZygoteForked() {
+  // TODO(skyostil): Disable the zygote host.
+}
+
+// static
+HeadlessContentMainDelegate* HeadlessContentMainDelegate::GetInstance() {
+  return g_current_headless_content_main_delegate;
+}
+
+// static
+void HeadlessContentMainDelegate::InitializeResourceBundle() {
+  base::FilePath pak_file;
+  bool r = PathService::Get(base::DIR_MODULE, &pak_file);

[Ryan Sleevi, 2016/02/25 22:04:36]

STYLE: "r" is not descriptive enough.

[Sami, 2016/02/26 18:49:16]

Done.

+  DCHECK(r);
+  pak_file = pak_file.Append(FILE_PATH_LITERAL("headless_lib.pak"));
+  ui::ResourceBundle::InitSharedInstanceWithPakPath(pak_file);
+}
+
+content::ContentBrowserClient*
+HeadlessContentMainDelegate::CreateContentBrowserClient() {
+  browser_client_.reset(new HeadlessContentBrowserClient(browser_.get()));
+  return browser_client_.get();
+}
+
+content::ContentRendererClient*
+HeadlessContentMainDelegate::CreateContentRendererClient() {
+  renderer_client_.reset(new HeadlessContentRendererClient);
+  return renderer_client_.get();
+}
+
+content::ContentUtilityClient*
+HeadlessContentMainDelegate::CreateContentUtilityClient() {
+  utility_client_.reset(new HeadlessContentUtilityClient);
+  return utility_client_.get();
+}
+
+}  // namespace headless