Require a user gesture to use navigator.share.

third_party/WebKit/LayoutTests/webshare/share-without-user-gesture.html

Index: third_party/WebKit/LayoutTests/webshare/share-without-user-gesture.html
diff --git a/third_party/WebKit/LayoutTests/webshare/share-error.html b/third_party/WebKit/LayoutTests/webshare/share-without-user-gesture.html
similarity index 81%
copy from third_party/WebKit/LayoutTests/webshare/share-error.html
copy to third_party/WebKit/LayoutTests/webshare/share-without-user-gesture.html
index 267f0e41ac42c926415cdb4afd8c73fd1938d998..bd681b63bb6b43ede2ed6af7e83b72f0d771f28f 100644
--- a/third_party/WebKit/LayoutTests/webshare/share-error.html
+++ b/third_party/WebKit/LayoutTests/webshare/share-without-user-gesture.html
@@ -8,7 +8,7 @@
 share_test((t, mock) => {
   mock.pushShareResult('the title', 'the message', 'error from browser');

[Matt Giuca, 2016/08/08 08:00:06]

I think this test should be based on the success test, not the error test. That
is, it should be a case that *would* succeed, were it not for the SecurityError.

[Sam McNally, 2016/08/08 09:08:44]

Removed this line entirely so the mock will cause a test failure if the call
succeeds.

[Matt Giuca, 2016/08/09 00:09:26]

Right, my reading of the code is that it will fail with "Unexpected call to mojo
share method", right? If so, that's great.

[Sam McNally, 2016/08/09 01:24:36]

Yes.

   return promise_rejects(
-      t, new DOMException('error from browser', 'AbortError'),
+      t, new DOMException('Must be handling a user gesture to perform a share request.', 'SecurityError'),
       navigator.share({title: 'the title', text: 'the message'}));
 }, 'share with browser-side error');