Remove ability for users to launch ephemeral apps.

Test code can still do this.

BUG=517735

Review URL: https://codereview.chromium.org/1395043002

Cr-Commit-Position: refs/heads/master@{#353904}

chrome/app/generated_resources.grd

@@ -6329,12 +6329,6 @@ Keep your key file in a safe place. You will need it to create new versions of y
       <message name="IDS_FLAGS_ENABLE_HOSTED_APP_QUIT_NOTIFICATION_DESCRIPTION" desc="Description for the flag to enable a notification when quitting with hosted apps.">
         Display a notification when quitting Chrome if hosted apps are currently running.
       </message>
-      <message name="IDS_FLAGS_ENABLE_EPHEMERAL_APPS_IN_WEBSTORE_NAME" desc="Name of the flag to enable ephemeral apps in the webstore.">
-        Enable experimental ephemeral apps from the webstore.
-      </message>
-      <message name="IDS_FLAGS_ENABLE_EPHEMERAL_APPS_IN_WEBSTORE_DESCRIPTION" desc="Description for the flag to enable ephemeral apps.">
-        Enables ephemeral apps, which are launched without installing in Chrome, to be launched from the Chrome WebStore. Requires the experimental App Launcher to be enabled.
-      </message>
       <if expr="is_android">
         <message name="IDS_FLAGS_DISABLE_PULL_TO_REFRESH_EFFECT_NAME" desc="Name of the flag to disable the pull-to-refresh effect.">
           Disable the pull-to-refresh effect.

chrome/browser/about_flags.cc

@@ -1458,11 +1458,6 @@ const Experiment kExperiments[] = {
      kOsMac,
      SINGLE_VALUE_TYPE(switches::kHostedAppQuitNotification)},
 #endif
-    {"enable-ephemeral-apps-in-webstore",
-     IDS_FLAGS_ENABLE_EPHEMERAL_APPS_IN_WEBSTORE_NAME,
-     IDS_FLAGS_ENABLE_EPHEMERAL_APPS_IN_WEBSTORE_DESCRIPTION,
-     kOsAll,
-     SINGLE_VALUE_TYPE(switches::kEnableEphemeralAppsInWebstore)},
 #if defined(OS_ANDROID)
     {"disable-pull-to-refresh-effect",
      IDS_FLAGS_DISABLE_PULL_TO_REFRESH_EFFECT_NAME,