Adding support checks for FileSystem APIs and making APIs not webkit-specific.

sdk/lib/html/dart2js/html_dart2js.dart

Index: sdk/lib/html/dart2js/html_dart2js.dart
diff --git a/sdk/lib/html/dart2js/html_dart2js.dart b/sdk/lib/html/dart2js/html_dart2js.dart
index 5246c4b2265abf93f758f3321a31a95a6933d791..d847db642bc40acd88efa8399dca294518145442 100644
--- a/sdk/lib/html/dart2js/html_dart2js.dart
+++ b/sdk/lib/html/dart2js/html_dart2js.dart
@@ -9863,6 +9863,9 @@ class FileReaderSync native "*FileReaderSync" {
 /// @domName DOMFileSystem; @docsEditable true
 class FileSystem native "*DOMFileSystem" {
 
+  /// Checks if this type is supported on the current platform.
+  static bool get supported => JS('bool', '!!(window.webkitRequestFileSystem)');
+
   /// @domName DOMFileSystem.name; @docsEditable true
   final String name;
 
@@ -22780,11 +22783,14 @@ class Window extends EventTarget implements WindowBase native "@*DOMWindow" {
   Point webkitConvertPointFromPageToNode(Node node, Point p) native;
 
   /// @domName DOMWindow.webkitRequestFileSystem; @docsEditable true
-  void webkitRequestFileSystem(int type, int size, FileSystemCallback successCallback, [ErrorCallback errorCallback]) native;
+  @JSName('webkitRequestFileSystem')
+  @SupportedBrowser(SupportedBrowser.CHROME) @Experimental()
+  void requestFileSystem(int type, int size, FileSystemCallback successCallback, [ErrorCallback errorCallback]) native;
 
   /// @domName DOMWindow.webkitResolveLocalFileSystemURL; @docsEditable true
   @JSName('webkitResolveLocalFileSystemURL')
-  void webkitResolveLocalFileSystemUrl(String url, EntryCallback successCallback, [ErrorCallback errorCallback]) native;
+  @SupportedBrowser(SupportedBrowser.CHROME) @Experimental()
+  void resolveLocalFileSystemUrl(String url, EntryCallback successCallback, [ErrorCallback errorCallback]) native;
 
   Stream<Event> get onContentLoaded => contentLoadedEvent.forTarget(this);
 
@@ -23278,18 +23284,24 @@ class WorkerContext extends EventTarget native "*WorkerContext" {
   int setTimeout(TimeoutHandler handler, int timeout) native;
 
   /// @domName WorkerContext.webkitRequestFileSystem; @docsEditable true
-  void webkitRequestFileSystem(int type, int size, [FileSystemCallback successCallback, ErrorCallback errorCallback]) native;
+  @JSName('webkitRequestFileSystem')
+  @SupportedBrowser(SupportedBrowser.CHROME) @Experimental()
+  void requestFileSystem(int type, int size, [FileSystemCallback successCallback, ErrorCallback errorCallback]) native;
 
   /// @domName WorkerContext.webkitRequestFileSystemSync; @docsEditable true
-  FileSystemSync webkitRequestFileSystemSync(int type, int size) native;
+  @JSName('webkitRequestFileSystemSync')
+  @SupportedBrowser(SupportedBrowser.CHROME) @Experimental()
+  FileSystemSync requestFileSystemSync(int type, int size) native;
 
   /// @domName WorkerContext.webkitResolveLocalFileSystemSyncURL; @docsEditable true
   @JSName('webkitResolveLocalFileSystemSyncURL')
-  EntrySync webkitResolveLocalFileSystemSyncUrl(String url) native;
+  @SupportedBrowser(SupportedBrowser.CHROME) @Experimental()
+  EntrySync resolveLocalFileSystemSyncUrl(String url) native;
 
   /// @domName WorkerContext.webkitResolveLocalFileSystemURL; @docsEditable true
   @JSName('webkitResolveLocalFileSystemURL')
-  void webkitResolveLocalFileSystemUrl(String url, EntryCallback successCallback, [ErrorCallback errorCallback]) native;
+  @SupportedBrowser(SupportedBrowser.CHROME) @Experimental()
+  void resolveLocalFileSystemUrl(String url, EntryCallback successCallback, [ErrorCallback errorCallback]) native;
 
   Stream<Event> get onError => errorEvent.forTarget(this);