Enable Touch Feedback Experiment by default
Change touch feedback switch to be a disabling switch. Update locations currently referencing the switch. Update unittests to no longer set the flag as it will be on by default.

TEST=SystemTrayTest.TrayPopupItemContainerTouchFeedback, SystemTrayTest.TrayPopupItemContainerTouchFeedbackCancellation, TrayDetailsViewTest.HoverHighlightViewTouchFeedback, TrayDetailsViewTest.HoverHighlightViewTouchFeedbackCancellation, MenuButtonTest.TouchFeedbackDuringTap, MenuButtonTest.TouchFeedbackDuringTapCancel

Review URL: https://codereview.chromium.org/752163003

Cr-Commit-Position: refs/heads/master@{#306298}
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index ca82ffd..0a2e6f86 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -958,11 +958,11 @@
     SINGLE_VALUE_TYPE(ash::switches::kAshEnableTouchViewTesting),
   },
   {
-    "enable-touch-feedback",
-    IDS_FLAGS_ENABLE_TOUCH_FEEDBACK_NAME,
-    IDS_FLAGS_ENABLE_TOUCH_FEEDBACK_DESCRIPTION,
+    "disable-touch-feedback",
+    IDS_FLAGS_DISABLE_TOUCH_FEEDBACK_NAME,
+    IDS_FLAGS_DISABLE_TOUCH_FEEDBACK_DESCRIPTION,
     kOsCrOS,
-    SINGLE_VALUE_TYPE(switches::kEnableTouchFeedback),
+    SINGLE_VALUE_TYPE(switches::kDisableTouchFeedback),
   },
   { "ash-disable-text-filtering-in-overview-mode",
     IDS_FLAGS_ASH_DISABLE_TEXT_FILTERING_IN_OVERVIEW_MODE_NAME,