DevTools: teach automapping to map complex sourcemap setups.

third_party/WebKit/Source/devtools/front_end/sdk/SourceMap.js

Index: third_party/WebKit/Source/devtools/front_end/sdk/SourceMap.js
diff --git a/third_party/WebKit/Source/devtools/front_end/sdk/SourceMap.js b/third_party/WebKit/Source/devtools/front_end/sdk/SourceMap.js
index 24dbe1dc424846aada9b9818c842ceb6fad31fe7..a7645e077be926263bac21ec2ea44616483fceb1 100644
--- a/third_party/WebKit/Source/devtools/front_end/sdk/SourceMap.js
+++ b/third_party/WebKit/Source/devtools/front_end/sdk/SourceMap.js
@@ -423,7 +423,7 @@ SDK.TextSourceMap = class {
       var url = Common.ParsedURL.completeURL(this._sourceMappingURL, href) || href;
       var source = sourceMap.sourcesContent && sourceMap.sourcesContent[i];
       if (url === this._compiledURL && source)
-        url += Common.UIString(' [sm]');
+        url += Common.UIString('? [sm]');
       this._sourceInfos.set(url, new SDK.TextSourceMap.SourceInfo(source, null));
       sourcesList.push(url);
     }