DevTools: enable target domain handler on the browser target, make browser target non-discoverable.

content/browser/devtools/browser_devtools_agent_host.h

Index: content/browser/devtools/browser_devtools_agent_host.h
diff --git a/content/browser/devtools/browser_devtools_agent_host.h b/content/browser/devtools/browser_devtools_agent_host.h
index 527fc5f00c7f3af07fd98440d74fafae5d1fbdd2..b2db86229ec44f3b34c03fe585fd8f854a5a4c54 100644
--- a/content/browser/devtools/browser_devtools_agent_host.h
+++ b/content/browser/devtools/browser_devtools_agent_host.h
@@ -12,11 +12,24 @@ namespace content {
 class DevToolsProtocolHandler;
 
 namespace devtools {
-namespace io { class IOHandler; }
-namespace memory { class MemoryHandler; }
-namespace system_info { class SystemInfoHandler; }
-namespace tethering { class TetheringHandler; }
-namespace tracing { class TracingHandler; }
+namespace io {
+class IOHandler;
+}
+namespace memory {
+class MemoryHandler;
+}
+namespace system_info {
+class SystemInfoHandler;
+}
+namespace target {
+class TargetHandler;
+}
+namespace tethering {
+class TetheringHandler;
+}
+namespace tracing {
+class TracingHandler;
+}
 }  // namespace devtools
 
 class BrowserDevToolsAgentHost : public DevToolsAgentHostImpl {
@@ -44,6 +57,7 @@ class BrowserDevToolsAgentHost : public DevToolsAgentHostImpl {
   std::unique_ptr<devtools::memory::MemoryHandler> memory_handler_;
   std::unique_ptr<devtools::system_info::SystemInfoHandler>
       system_info_handler_;
+  std::unique_ptr<devtools::target::TargetHandler> target_handler_;
   std::unique_ptr<devtools::tethering::TetheringHandler> tethering_handler_;
   std::unique_ptr<devtools::tracing::TracingHandler> tracing_handler_;
   std::unique_ptr<DevToolsProtocolHandler> protocol_handler_;