Disable failing PolicyPrefsTest.PolicyToPrefsMapping test

TBR: bartfab@chromium.org
Bug: 803755
Change-Id: I005ee35f23837eb2c6f0209be502701540d1ec0c
Reviewed-on: https://chromium-review.googlesource.com/875685Reviewed-by: Yoichi Osato <yoichio@chromium.org>
Commit-Queue: Yoichi Osato <yoichio@chromium.org>
Cr-Commit-Position: refs/heads/master@{#530460}

chrome/browser/policy/policy_prefs_browsertest.cc

@@ -457,7 +457,8 @@ class PolicyPrefsTest : public InProcessBrowserTest {
 
 // Verifies that policies make their corresponding preferences become managed,
 // and that the user can't override that setting.
-IN_PROC_BROWSER_TEST_F(PolicyPrefsTest, PolicyToPrefsMapping) {
+// Failed on all platforms. See crbug.com/803755.
+IN_PROC_BROWSER_TEST_F(PolicyPrefsTest, DISABLED_PolicyToPrefsMapping) {
   Schema chrome_schema = Schema::Wrap(GetChromeSchemaData());
   ASSERT_TRUE(chrome_schema.valid());
   PrefService* local_state = g_browser_process->local_state();