File constructor understands lastModified.

Source/bindings/v8/custom/V8FileCustom.cpp

Index: Source/bindings/v8/custom/V8FileCustom.cpp
diff --git a/Source/bindings/v8/custom/V8FileCustom.cpp b/Source/bindings/v8/custom/V8FileCustom.cpp
index 6983ef2188946414cbbeb6a688c5b9914d1d3b51..1971063bc7f820f7c02c3399768e38e2cae97f6e 100644
--- a/Source/bindings/v8/custom/V8FileCustom.cpp
+++ b/Source/bindings/v8/custom/V8FileCustom.cpp
@@ -62,25 +62,46 @@ void V8File::constructorCustom(const v8::FunctionCallbackInfo<v8::Value>& info)
 
     V8TRYCATCH_FOR_V8STRINGRESOURCE_VOID(V8StringResource<>, fileName, info[1]);
 
-    String contentType;
-    String endings = "transparent"; // default if no BlobPropertyBag is passed
+    V8BlobCustomHelpers::ParsedProperties properties(true);
     if (info.Length() > 2) {
         if (!info[2]->IsObject()) {
             throwTypeError(ExceptionMessages::failedToConstruct("File", "The 3rd argument is not of type Object."), info.GetIsolate());
             return;
         }
 
-        if (!V8BlobCustomHelpers::processBlobPropertyBag(info[2], "File", contentType, endings, info.GetIsolate()))
+        if (!properties.parseBlobPropertyBag(info[2], "File", info.GetIsolate()))
             return;
+    } else {
+        properties.setDefaultLastModifiedDate();
     }
 
     BlobBuilder blobBuilder;
     v8::Local<v8::Object> blobParts = v8::Local<v8::Object>::Cast(info[0]);
-    if (!V8BlobCustomHelpers::processBlobParts(blobParts, length, endings, blobBuilder, info.GetIsolate()))
+    if (!V8BlobCustomHelpers::processBlobParts(blobParts, length, properties.endings, blobBuilder, info.GetIsolate()))
         return;
 
-    RefPtr<File> file = blobBuilder.createFile(contentType, fileName, currentTime());
+    RefPtr<File> file = blobBuilder.createFile(properties.contentType, fileName, properties.lastModifiedDate());
     v8SetReturnValue(info, file.release());
 }
 
+void V8File::lastModifiedDateAttributeGetterCustom(const v8::PropertyCallbackInfo<v8::Value>& info)
+{
+    // The auto-generated getters return null when the method in the underlying
+    // implementation returns NaN. Here, we need to return a Date whose value
+    // is NaN when the File constructor receives such a Date. WebIDL calls it
+    // an "undefined date". Fortunately, lastModifiedDate never needs to return
+    // null, so we can get away with mapping NaN to "new Date(NaN)" instead of
+    // "null".
+    //
+    // See step 3.3 in Section 7.1, and Section 7.2 of the File API spec:
+    // http://dev.w3.org/2006/webapi/FileAPI/
+    //
+    // See the following sections of the WebIDL ED:
+    // 3.10.26: http://heycam.github.io/webidl/#idl-Date
+    // 4.2.27: http://heycam.github.io/webidl/#es-Date
+
+    File* file = V8File::toNative(info.Holder());
+    v8SetReturnValue(info, v8::Date::New(file->lastModifiedDate()));
+}
+
 } // namespace WebCore