headless: Move creation of DevTools clients after browser startup

This prepares for replacing GetTaskRunnerForThread() inside
HeadlessDevToolsClient::Create() with
base::CreateSingleThreadTaskRunnerWithTraits(), which can only be
called after browser initialization.

Bug: 878356
Change-Id: I851788ee9926cddd4662876c84e98a1fb9d0d47e
Reviewed-on: https://chromium-review.googlesource.com/1193367
Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Commit-Queue: Eric Seckler <eseckler@chromium.org>
Cr-Commit-Position: refs/heads/master@{#586698}

headless/app/headless_shell.cc

@@ -141,7 +141,6 @@ base::FilePath GetSSLKeyLogFile(const base::CommandLine* command_line) {
 
 HeadlessShell::HeadlessShell()
     : browser_(nullptr),
-      devtools_client_(HeadlessDevToolsClient::Create()),
 #if !defined(CHROME_MULTIPLE_DLL_CHILD)
       web_contents_(nullptr),
       browser_context_(nullptr),
@@ -155,6 +154,7 @@ HeadlessShell::~HeadlessShell() = default;
 #if !defined(CHROME_MULTIPLE_DLL_CHILD)
 void HeadlessShell::OnStart(HeadlessBrowser* browser) {
   browser_ = browser;
+  devtools_client_ = HeadlessDevToolsClient::Create();
   file_task_runner_ = base::CreateSequencedTaskRunnerWithTraits(
       {base::MayBlock(), base::TaskPriority::BEST_EFFORT});
 

headless/lib/headless_browser_browsertest.cc

@@ -418,7 +418,7 @@ class CrashReporterTest : public HeadlessBrowserTest,
                           public HeadlessWebContents::Observer,
                           inspector::ExperimentalObserver {
  public:
-  CrashReporterTest() : devtools_client_(HeadlessDevToolsClient::Create()) {}
+  CrashReporterTest() {}
   ~CrashReporterTest() override = default;
 
   void SetUp() override {
@@ -439,6 +439,7 @@ class CrashReporterTest : public HeadlessBrowserTest,
   // HeadlessWebContents::Observer implementation:
   void DevToolsTargetReady() override {
     EXPECT_TRUE(web_contents_->GetDevToolsTarget());
+    devtools_client_ = HeadlessDevToolsClient::Create();
     web_contents_->GetDevToolsTarget()->AttachClient(devtools_client_.get());
     devtools_client_->GetInspector()->GetExperimental()->AddObserver(this);
   }

headless/lib/headless_browser_context_browsertest.cc

@@ -45,9 +45,7 @@ class HeadlessBrowserContextIsolationTest
     : public HeadlessAsyncDevTooledBrowserTest {
  public:
   HeadlessBrowserContextIsolationTest()
-      : browser_context_(nullptr),
-        web_contents2_(nullptr),
-        devtools_client2_(HeadlessDevToolsClient::Create()) {
+      : browser_context_(nullptr), web_contents2_(nullptr) {
     EXPECT_TRUE(embedded_test_server()->Start());
   }
 
@@ -60,6 +58,7 @@ class HeadlessBrowserContextIsolationTest
       return;
     }
 
+    devtools_client2_ = HeadlessDevToolsClient::Create();
     web_contents2_->GetDevToolsTarget()->AttachClient(devtools_client2_.get());
     HeadlessAsyncDevTooledBrowserTest::DevToolsTargetReady();
   }

headless/lib/headless_web_contents_browsertest.cc

@@ -447,9 +447,7 @@ class HeadlessWebContentsBeginFrameControlTest
       public headless_experimental::ExperimentalObserver,
       public page::Observer {
  public:
-  HeadlessWebContentsBeginFrameControlTest()
-      : browser_devtools_client_(HeadlessDevToolsClient::Create()),
-        devtools_client_(HeadlessDevToolsClient::Create()) {}
+  HeadlessWebContentsBeginFrameControlTest() {}
 
   void SetUp() override {
     EnablePixelOutput();
@@ -463,6 +461,8 @@ class HeadlessWebContentsBeginFrameControlTest
       std::unique_ptr<headless_experimental::BeginFrameResult> result) {}
 
   void RunTest() {
+    browser_devtools_client_ = HeadlessDevToolsClient::Create();
+    devtools_client_ = HeadlessDevToolsClient::Create();
     browser_context_ = browser()->CreateBrowserContextBuilder().Build();
     browser()->SetDefaultBrowserContext(browser_context_);
     browser()->GetDevToolsTarget()->AttachClient(

headless/test/headless_browser_test.cc

@@ -227,8 +227,6 @@ void HeadlessBrowserTest::FinishAsynchronousTest() {
 HeadlessAsyncDevTooledBrowserTest::HeadlessAsyncDevTooledBrowserTest()
     : browser_context_(nullptr),
       web_contents_(nullptr),
-      devtools_client_(HeadlessDevToolsClient::Create()),
-      browser_devtools_client_(HeadlessDevToolsClient::Create()),
       render_process_exited_(false) {}
 
 HeadlessAsyncDevTooledBrowserTest::~HeadlessAsyncDevTooledBrowserTest() =
@@ -252,6 +250,8 @@ void HeadlessAsyncDevTooledBrowserTest::RenderProcessExited(
 }
 
 void HeadlessAsyncDevTooledBrowserTest::RunTest() {
+  devtools_client_ = HeadlessDevToolsClient::Create();
+  browser_devtools_client_ = HeadlessDevToolsClient::Create();
   interceptor_ = std::make_unique<TestNetworkInterceptor>();
   HeadlessBrowserContext::Builder builder =
       browser()->CreateBrowserContextBuilder();