Add Page.stopLoading to devtools and --timeout switch to headless_shell

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

 {
     "version": { "major": "1", "minor": "2" },
     "domains": [{
         "domain": "Inspector",
         "experimental": true,
         "types": [],
         "commands": [
             {
                 "name": "enable",
                 "description": "Enables inspector domain notifications."
@@ skipping 241 matching lines @@
                 "name": "navigate",
                 "parameters": [
                     { "name": "url", "type": "string", "description": "URL to navigate the page to." }
                 ],
                 "returns": [
                     { "name": "frameId", "$ref": "FrameId", "experimental": true, "description": "Frame id that will be navigated." }
                 ],
                 "description": "Navigates current page to the given URL."
             },
             {
+                "name": "stopLoading",
+                "description": "Force the page stop all navigations and pending resource fetches.",
+                "experimental": true
+            },
+            {
               "name": "getNavigationHistory",
               "returns": [
                 { "name": "currentIndex", "type": "integer", "description": "Index of the current navigation history entry." },
                 { "name": "entries", "type": "array", "items": { "$ref": "NavigationEntry" }, "description": "Array of navigation history entries." }
               ],
               "description": "Returns navigation history for the current page.",
               "experimental": true
             },
             {
               "name": "navigateToHistoryEntry",
@@ skipping 4215 matching lines @@
                 "name": "accepted",
                 "description": "Informs that port was successfully bound and got a specified connection id.",
                 "parameters": [
                     {"name": "port", "type": "integer", "description": "Port number that was successfully bound." },
                     {"name": "connectionId", "type": "string", "description": "Connection id to be used." }
                 ]
             }
         ]
     }]
 }