Disable flaky GenericSensorBrowserTest.AmbientLightSensorTest on Windows

Bug: 809537
Change-Id: I54951259e0b64944c92c0d28e06f16e4584b7460
TBR: reillyg@chromium.org
Reviewed-on: https://chromium-review.googlesource.com/904643Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Cr-Commit-Position: refs/heads/master@{#534694}

content/browser/generic_sensor_browsertest.cc

@@ -253,7 +253,8 @@ class GenericSensorBrowserTest : public ContentBrowserTest {
 };
 
 // Flakily crashes on Linux ASAN/TSAN bots.  https://crbug.com/789515
-#if defined(OS_LINUX)
+// Flakily times out on Windows bots.  https://crbug.com/809537
+#if defined(OS_LINUX) || defined(OS_WIN)
 #define MAYBE_AmbientLightSensorTest DISABLED_AmbientLightSensorTest
 #else
 #define MAYBE_AmbientLightSensorTest AmbientLightSensorTest