DevTools: explicitly control support for viewport meta tag so that desktop emulation was possible

Source/devtools/protocol.json

 {
     "version": { "major": "1", "minor": "1" },
     "domains": [{
         "domain": "Inspector",
         "hidden": true,
         "types": [],
         "commands": [
             {
                 "name": "enable",
                 "description": "Enables inspector domain notifications."
@@ skipping 298 matching lines @@
                 ],
                 "hidden": true
             },
             {
                 "name": "setDeviceMetricsOverride",
                 "description": "Overrides the values of device screen dimensions (window.screen.width, window.screen.height, window.innerWidth, window.innerHeight, and \"device-width\"/\"device-height\"-related CSS media query results) and the font scale factor.",
                 "parameters": [
                     { "name": "width", "type": "integer", "description": "Overriding width value in pixels (minimum 0, maximum 10000000). 0 disables the override." },
                     { "name": "height", "type": "integer", "description": "Overriding height value in pixels (minimum 0, maximum 10000000). 0 disables the override." },
                     { "name": "deviceScaleFactor", "type": "number", "description": "Overriding device scale factor value (must be positive)." },
+                    { "name": "emulateViewport", "type": "boolean", "description": "Whether viewport meta tag should be respected." },
                     { "name": "fitWindow", "type": "boolean", "description": "Whether a view that exceeds the available browser window area should be scaled down to fit." },
                     { "name": "textAutosizing", "type": "boolean", "optional": true, "description": "Whether to override the text autosizing feature." },
                     { "name": "fontScaleFactor", "type": "number", "optional": true, "description": "Overriding system font scale factor (must be positive)." }
                 ],
                 "hidden": true
             },
             {
                 "name": "setShowPaintRects",
                 "description": "Requests that backend shows paint rectangles",
                 "parameters": [
@@ skipping 3714 matching lines @@
                 "parameters": [
                     { "name": "value", "type": "array", "items": { "type": "object" } }
                 ]
             },
             {
                 "name": "tracingComplete"
             }
         ]
     }]
 }