Reduce test code duplication in fast/forms/file

LayoutTests/fast/forms/file/resources/file-drag-common.js

Index: LayoutTests/fast/forms/file/resources/file-drag-common.js
diff --git a/LayoutTests/fast/forms/file/resources/file-drag-common.js b/LayoutTests/fast/forms/file/resources/file-drag-common.js
new file mode 100644
index 0000000000000000000000000000000000000000..224e2b0f864d178af5889bfb5fcd0f72246e10e5
--- /dev/null
+++ b/LayoutTests/fast/forms/file/resources/file-drag-common.js
@@ -0,0 +1,19 @@
+function moveMouseToCenterOfElement(element) {
+    var centerX = element.offsetLeft + element.offsetWidth / 2;
+    var centerY = element.offsetTop + element.offsetHeight / 2;
+    eventSender.mouseMoveTo(centerX, centerY);
+}
+
+function dragFilesOntoInput(input, files) {
+    eventSender.beginDragWithFiles(files);
+    moveMouseToCenterOfElement(input);
+    eventSender.mouseUp();
+}
+
+function dragFilesOntoElement(element, files) {
+    eventSender.beginDragWithFiles(files);
+    var centerX = element.offsetLeft + element.offsetWidth / 2;
+    var centerY = element.offsetTop + element.offsetHeight / 2;
+    eventSender.mouseMoveTo(centerX, centerY);
+    eventSender.mouseUp();
+}