Add commands to manage tabs and contexts to Browser Domain

headless/lib/browser/headless_web_contents_impl.cc

Index: headless/lib/browser/headless_web_contents_impl.cc
diff --git a/headless/lib/browser/headless_web_contents_impl.cc b/headless/lib/browser/headless_web_contents_impl.cc
index b07cb2c7edef0e809b0bd0e3b756426ba09f6c88..a9bc987f434361aa1c7c24041936f1bf3578dcfd 100644
--- a/headless/lib/browser/headless_web_contents_impl.cc
+++ b/headless/lib/browser/headless_web_contents_impl.cc
@@ -27,6 +27,14 @@
 
 namespace headless {
 
+// static
+HeadlessWebContentsImpl* HeadlessWebContentsImpl::From(
+    HeadlessWebContents* web_contents) {
+  // This downcast is safe because there is only one implementation of
+  // HeadlessWebContents.
+  return static_cast<HeadlessWebContentsImpl*>(web_contents);
+}
+
 class WebContentsObserverAdapter : public content::WebContentsObserver {
  public:
   WebContentsObserverAdapter(content::WebContents* web_contents,
@@ -122,6 +130,12 @@ HeadlessWebContentsImpl::~HeadlessWebContentsImpl() {
   web_contents_->Close();
 }
 
+content::DevToolsAgentHost* HeadlessWebContentsImpl::EnsureDevToolsAgentHost() {
+  if (!agent_host_)
+    agent_host_ = content::DevToolsAgentHost::GetOrCreateFor(web_contents());
+  return agent_host_.get();
+}
+
 bool HeadlessWebContentsImpl::OpenURL(const GURL& url) {
   if (!url.is_valid())
     return false;
@@ -137,6 +151,10 @@ void HeadlessWebContentsImpl::Close() {
   browser_->DestroyWebContents(this);
 }
 
+std::string HeadlessWebContentsImpl::GetAgentHostId() {
+  return EnsureDevToolsAgentHost()->GetId();
+}
+
 void HeadlessWebContentsImpl::AddObserver(Observer* observer) {
   DCHECK(observer_map_.find(observer) == observer_map_.end());
   observer_map_[observer] = base::WrapUnique(
@@ -154,9 +172,8 @@ HeadlessDevToolsTarget* HeadlessWebContentsImpl::GetDevToolsTarget() {
 }
 
 void HeadlessWebContentsImpl::AttachClient(HeadlessDevToolsClient* client) {
-  if (!agent_host_)
-    agent_host_ = content::DevToolsAgentHost::GetOrCreateFor(web_contents());
-  HeadlessDevToolsClientImpl::From(client)->AttachToHost(agent_host_.get());
+  HeadlessDevToolsClientImpl::From(client)->AttachToHost(
+      EnsureDevToolsAgentHost());
 }
 
 void HeadlessWebContentsImpl::DetachClient(HeadlessDevToolsClient* client) {