WebBluetooth: Use [SecureContext] instead of manual check

Until now, we had to use IsSecureContext() to check whether an execution
context is a secure context manually. But we can use [SecureContext]
instead of the manual check now.

Bug: none
Change-Id: Ibfcd4a9a2eed3e7ac67819b9bf4204f4c73412d8
Reviewed-on: https://chromium-review.googlesource.com/990014Reviewed-by: Giovanni Ortuño Urquidi <ortuno@chromium.org>
Commit-Queue: Jinho Bang <jinho.bang@samsung.com>
Cr-Commit-Position: refs/heads/master@{#548464}

third_party/WebKit/LayoutTests/http/tests/security/powerfulFeatureRestrictions/bluetooth-on-insecure-origin.html

@@ -7,11 +7,8 @@
 if (window.location.origin != get_host_info().UNAUTHENTICATED_ORIGIN) {
     window.location = get_host_info().UNAUTHENTICATED_ORIGIN + window.location.pathname;
 } else {
-    promise_test(function(test) {
-        return promise_rejects(test, 'SecurityError',
-          navigator.bluetooth.requestDevice({
-            filters: [{services: ['generic_access']}]
-          }));
-    }, "Requires secure context before user gesture");
+    test(t => {
+        assert_false('requestDevice' in navigator.bluetooth, 'navigator.bluetooth.requestDevice should not be present');
+    }, 'navigator.bluetooth.requestDevice requires a secure context');
 }
 </script>

third_party/WebKit/Source/modules/bluetooth/Bluetooth.cpp

@@ -164,13 +164,7 @@ ScriptPromise Bluetooth::requestDevice(ScriptState* script_state,
       "implementation-status.md"));
 #endif
 
-  // If the Relevant settings object is not a secure context, reject promise
-  // with a SecurityError and abort these steps.
-  String error_message;
-  if (!context->IsSecureContext(error_message)) {
-    return ScriptPromise::RejectWithDOMException(
-        script_state, DOMException::Create(kSecurityError, error_message));
-  }
+  CHECK(context->IsSecureContext());
 
   // If the algorithm is not allowed to show a popup, reject promise with a
   // SecurityError and abort these steps.

third_party/WebKit/Source/modules/bluetooth/Bluetooth.idl

@@ -7,5 +7,5 @@
 [
     RuntimeEnabled=WebBluetooth
 ] interface Bluetooth {
-    [CallWith=ScriptState, RaisesException, MeasureAs=WebBluetoothRequestDevice] Promise<BluetoothDevice> requestDevice (optional RequestDeviceOptions options);
+    [CallWith=ScriptState, RaisesException, MeasureAs=WebBluetoothRequestDevice, SecureContext] Promise<BluetoothDevice> requestDevice (optional RequestDeviceOptions options);
 };