Disable InputRouterImplScaleGestureEventTest.GestureFlingStart on Fuchsia.

This test is flaky on Fuchsia.

TBR=treib@chromium.org,sfiera@chromium.org,sahel@chromium.org,tdresser@chromium.org

Bug: 807803
Change-Id: Ie05cca6552c447af612bb36cb86663a8ba118b05
Reviewed-on: https://chromium-review.googlesource.com/898763
Commit-Queue: Yuta Kitamura <yutak@chromium.org>
Reviewed-by: Yuta Kitamura <yutak@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533976}

content/browser/renderer_host/input/input_router_impl_unittest.cc

@@ -2342,7 +2342,13 @@ TEST_F(InputRouterImplScaleGestureEventTest, GestureTwoFingerTap) {
   EXPECT_EQ(40, filter_event->data.two_finger_tap.first_finger_height);
 }
 
-TEST_F(InputRouterImplScaleGestureEventTest, GestureFlingStart) {
+// Thie test is flaky on Fuchsia. crbug.com/807803
+#if defined(OS_FUCHSIA)
+#define MAYBE_GestureFlingStart DISABLED_GestureFlingStart
+#else
+#define MAYBE_GestureFlingStart GestureFlingStart
+#endif
+TEST_F(InputRouterImplScaleGestureEventTest, MAYBE_GestureFlingStart) {
   // Simulate a GSB since touchscreen flings must happen inside scroll.
   SimulateGestureEvent(SyntheticWebGestureEventBuilder::BuildScrollBegin(
       10.f, 20.f, blink::kWebGestureDeviceTouchscreen));