Only disable InputEventRouterTouchpadGestureTargetTest under viz hit testing

Versions /1 and /2 (viz hit testing) are flaky, but /0 is fine, so we'll
keep /0 enabled.

Bug: 838835
Change-Id: If535c37a49d8f251283712f7b2e280ad60efebd9
Reviewed-on: https://chromium-review.googlesource.com/1042487Reviewed-by: Ken Buchanan <kenrb@chromium.org>
Commit-Queue: Kevin McNee <mcnee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555774}

content/browser/site_per_process_hit_test_browsertest.cc

@@ -3022,9 +3022,14 @@ IN_PROC_BROWSER_TEST_P(
 }
 #endif  // defined(USE_AURA) || defined(OS_ANDROID)
 
-// Flaky, see crbug.com/838835
 IN_PROC_BROWSER_TEST_P(SitePerProcessHitTestBrowserTest,
-                       DISABLED_InputEventRouterTouchpadGestureTargetTest) {
+                       InputEventRouterTouchpadGestureTargetTest) {
+  // TODO(838835): Flaky with viz hit testing
+  if (features::IsVizHitTestingEnabled()) {
+    LOG(INFO) << "Skipping test due to https://crbug.com/838835";
+    return;
+  }
+
   GURL main_url(embedded_test_server()->GetURL(
       "/frame_tree/page_with_positioned_nested_frames.html"));
   EXPECT_TRUE(NavigateToURL(shell(), main_url));