DevTools: consistently use relative name for filesystem resources.

third_party/WebKit/Source/devtools/front_end/persistence/FileSystemWorkspaceBinding.js

Index: third_party/WebKit/Source/devtools/front_end/persistence/FileSystemWorkspaceBinding.js
diff --git a/third_party/WebKit/Source/devtools/front_end/persistence/FileSystemWorkspaceBinding.js b/third_party/WebKit/Source/devtools/front_end/persistence/FileSystemWorkspaceBinding.js
index 8091642bebe380935fc48ef7a856273015a9bb6b..9eec9776bc00fe82e095dac8054272856821c7aa 100644
--- a/third_party/WebKit/Source/devtools/front_end/persistence/FileSystemWorkspaceBinding.js
+++ b/third_party/WebKit/Source/devtools/front_end/persistence/FileSystemWorkspaceBinding.js
@@ -198,6 +198,7 @@ Persistence.FileSystemWorkspaceBinding.FileSystem = class extends Workspace.Proj
 
     this._fileSystem = isolatedFileSystem;
     this._fileSystemBaseURL = this._fileSystem.path() + '/';
+    this._fileSystemParentURL = this._fileSystemBaseURL.substr(0, fileSystemPath.lastIndexOf('/') + 1);
     this._fileSystemWorkspaceBinding = fileSystemWorkspaceBinding;
     this._fileSystemPath = fileSystemPath;
 
@@ -305,6 +306,17 @@ Persistence.FileSystemWorkspaceBinding.FileSystem = class extends Workspace.Proj
 
   /**
    * @override
+   * @param {!Workspace.UISourceCode} uiSourceCode
+   * @return {string}
+   */
+  fullDisplayName(uiSourceCode) {
+    var baseURL =
+        /** @type {!Persistence.FileSystemWorkspaceBinding.FileSystem}*/ (uiSourceCode.project())._fileSystemParentURL;
+    return uiSourceCode.url().substring(baseURL.length);
+  }
+
+  /**
+   * @override
    * @return {boolean}
    */
   canRename() {