DevTools: expose length of the stylesheet content in protocol

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 2754 matching lines @@
                     { "name": "frameId", "$ref": "Page.FrameId", "description": "Owner frame identifier."},
                     { "name": "sourceURL", "type": "string", "description": "Stylesheet resource URL."},
                     { "name": "sourceMapURL", "type": "string", "optional": true, "description": "URL of source map associated with the stylesheet (if any)." },
                     { "name": "origin", "$ref": "StyleSheetOrigin", "description": "Stylesheet origin."},
                     { "name": "title", "type": "string", "description": "Stylesheet title."},
                     { "name": "ownerNode", "$ref": "DOM.BackendNodeId", "optional": true, "description": "The backend id for the owner node of the stylesheet." },
                     { "name": "disabled", "type": "boolean", "description": "Denotes whether the stylesheet is disabled."},
                     { "name": "hasSourceURL", "type": "boolean", "optional": true, "description": "Whether the sourceURL field value comes from the sourceURL comment." },
                     { "name": "isInline", "type": "boolean", "description": "Whether this stylesheet is created for STYLE tag by parser. This flag is not set for document.written STYLE tags." },
                     { "name": "startLine", "type": "number", "description": "Line offset of the stylesheet within the resource (zero based)." },
-                    { "name": "startColumn", "type": "number", "description": "Column offset of the stylesheet within the resource (zero based)." }
+                    { "name": "startColumn", "type": "number", "description": "Column offset of the stylesheet within the resource (zero based)." },
+                    { "name": "length", "type": "number", "description": "Size of the content (in characters).", "experimental": true }
                 ],
                 "description": "CSS stylesheet metainformation."
             },
             {
                 "id": "CSSRule",
                 "type": "object",
                 "properties": [
                     { "name": "styleSheetId", "$ref": "StyleSheetId", "optional": true, "description": "The css style sheet identifier (absent for user agent stylesheet and user-specified stylesheet rules) this rule came from." },
                     { "name": "selectorList", "$ref": "SelectorList", "description": "Rule selector data." },
                     { "name": "origin", "$ref": "StyleSheetOrigin", "description": "Parent stylesheet's origin."},
@@ skipping 1765 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." }
                 ]
             }
         ]
     }]
 }