Add a simple scrollable_page to test/data.

This cl adds a simple scrollable_page.html to make sure that navigation
to scrollable_page.html succeeds in the following test:
BrowserSideFlingBrowsersTest.FlingingStopsAfterNavigation

Bug: 922059
Change-Id: Id07192763216cae830cbd4e705e070245963223b
Reviewed-on: https://chromium-review.googlesource.com/c/1412596
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Sahel Sharify <sahel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#623464}
diff --git a/content/test/data/scrollable_page.html b/content/test/data/scrollable_page.html
new file mode 100644
index 0000000..b9e6f49
--- /dev/null
+++ b/content/test/data/scrollable_page.html
@@ -0,0 +1,10 @@
+<html>
+<head>
+  <meta name='viewport' content='width=device-width, minimum-scale=1'>
+</head>
+<style>
+body {
+  height: 10000px;
+  overflow: scroll;
+}
+</style>