DevTools: return discovered targets asynchronously.

third_party/WebKit/Source/core/inspector/browser_protocol.json

Index: third_party/WebKit/Source/core/inspector/browser_protocol.json
diff --git a/third_party/WebKit/Source/core/inspector/browser_protocol.json b/third_party/WebKit/Source/core/inspector/browser_protocol.json
index 295c1146e86522ec144f8b023b712f8f98e1eb6b..38dfebab2f98000ca18674e969f57d1d97034647 100644
--- a/third_party/WebKit/Source/core/inspector/browser_protocol.json
+++ b/third_party/WebKit/Source/core/inspector/browser_protocol.json
@@ -4391,7 +4391,8 @@
                     { "name": "targetInfo", "type": "array", "items": { "$ref": "TargetInfo" } }
                 ],
                 "description": "Returns target information for all potential targets.",
-                "handlers": ["browser"]
+                "handlers": ["browser"],
+                "async": true
             },
             {
                 "name": "attach",
@@ -4399,7 +4400,11 @@
                 "parameters": [
                     {"name": "targetId", "$ref": "TargetID", "description": "Target id." }
                 ],
-                "handlers": ["browser"]
+                "returns": [
+                    { "name": "success", "type": "boolean", "description": "Whether attach succeeded." }
+                ],
+                "handlers": ["browser"],
+                "async": true
             },
             {
                 "name": "detach",
@@ -4407,6 +4412,9 @@
                 "parameters": [
                     { "name": "targetId", "$ref": "TargetID" }
                 ],
+                "returns": [
+                    { "name": "success", "type": "boolean", "description": "Whether detach succeeded." }
+                ],
                 "handlers": ["browser"]
             },
             {