Enable WebUSB on Android.

This change finishes up the work done to remove #ifdefs disabling USB on
Android by making the WebUSB flag available on all platforms and
removing the #ifdef preventing the WebUSBClient from being provided to
the render frame on Android.

BUG=492204

Review URL: https://codereview.chromium.org/1493183002

Cr-Commit-Position: refs/heads/master@{#363826}
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index ade3803..8c05dd9 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -1978,15 +1978,13 @@
      ENABLE_DISABLE_VALUE_TYPE(switches::kEnablePushApiBackgroundMode,
                                switches::kDisablePushApiBackgroundMode)},
 #endif  // defined(ENABLE_BACKGROUND)
-#if !defined(OS_ANDROID) && !defined(OS_IOS)
-     // TODO(reillyg): Remove this flag when the permission granting UI is
-     // available. crbug.com/529950
-     {"enable-webusb-on-any-origin",
-      IDS_FLAGS_ENABLE_WEBUSB_ON_ANY_ORIGIN_NAME,
-      IDS_FLAGS_ENABLE_WEBUSB_ON_ANY_ORIGIN_DESCRIPTION,
-      kOsDesktop,
-      SINGLE_VALUE_TYPE(switches::kEnableWebUsbOnAnyOrigin)},
-#endif
+    // TODO(reillyg): Remove this flag when the permission granting UI is
+    // available. crbug.com/529950
+    {"enable-webusb-on-any-origin",
+     IDS_FLAGS_ENABLE_WEBUSB_ON_ANY_ORIGIN_NAME,
+     IDS_FLAGS_ENABLE_WEBUSB_ON_ANY_ORIGIN_DESCRIPTION,
+     kOsAll,
+     SINGLE_VALUE_TYPE(switches::kEnableWebUsbOnAnyOrigin)},
 #if defined(OS_CHROMEOS)
     {"cros-regions-mode",
      IDS_FLAGS_CROS_REGIONS_MODE_NAME,