chromeos: Enable "Show taps" mojo app by default

It seems to work properly, has tests, starts up quickly, and generates
proper crash reports. Turn it on for everybody.

Note: This app only runs if the user sets "Show taps" in about:flags
or passes the --show-taps command line switch.

Bug: 840380
Test: chrome --show-taps still shows touch points on the screen
Change-Id: I8df4dff6ecdd9f15ed4409112161152fbb344b00
Reviewed-on: https://chromium-review.googlesource.com/1067783
Commit-Queue: James Cook <jamescook@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#560361}

ash/public/cpp/ash_features.cc

@@ -26,7 +26,7 @@ const base::Feature kPersistentWindowBounds{"PersistentWindowBounds",
                                             base::FEATURE_ENABLED_BY_DEFAULT};
 
 const base::Feature kShowTapsApp{"ShowTapsApp",
-                                 base::FEATURE_DISABLED_BY_DEFAULT};
+                                 base::FEATURE_ENABLED_BY_DEFAULT};
 
 const base::Feature kSystemTrayUnified{"SystemTrayUnified",
                                        base::FEATURE_DISABLED_BY_DEFAULT};

ash/touch/touch_observer_hud_unittest.cc

@@ -4,6 +4,7 @@
 
 #include "ash/touch/touch_observer_hud.h"
 
+#include "ash/public/cpp/ash_features.h"
 #include "ash/public/cpp/ash_switches.h"
 #include "ash/public/cpp/config.h"
 #include "ash/root_window_controller.h"
@@ -16,6 +17,7 @@
 #include "base/command_line.h"
 #include "base/format_macros.h"
 #include "base/strings/stringprintf.h"
+#include "base/test/scoped_feature_list.h"
 #include "ui/aura/window.h"
 #include "ui/display/manager/display_manager.h"
 #include "ui/display/test/display_manager_test_api.h"
@@ -269,6 +271,7 @@ class TouchHudProjectionTest : public TouchHudTestBase {
   // testing::Test:
   void SetUp() override {
     base::CommandLine::ForCurrentProcess()->AppendSwitch(switches::kShowTaps);
+    scoped_feature_list_.InitAndDisableFeature(features::kShowTapsApp);
     TouchHudTestBase::SetUp();
   }
 
@@ -293,6 +296,7 @@ class TouchHudProjectionTest : public TouchHudTestBase {
   }
 
  private:
+  base::test::ScopedFeatureList scoped_feature_list_;
   base::TimeTicks event_time;
 
   DISALLOW_COPY_AND_ASSIGN(TouchHudProjectionTest);