Don't set lastError if chrome.dial.discoverNow() can't start; we always...

Don't set lastError if chrome.dial.discoverNow() can't start; we always attempt discovery and success/failure is indicated through the callback.

Add browser test for chrome.dial.discoverNow() success.

BUG=376588

Review URL: https://codereview.chromium.org/511943004

Cr-Commit-Position: refs/heads/master@{#292584}

chrome/browser/extensions/api/dial/dial_api.cc

@@ -19,8 +19,6 @@ using content::BrowserThread;
 
 namespace {
 
-const char kDialServiceError[] = "Dial service error.";
-
 // How often to poll for devices.
 const int kDialRefreshIntervalSecs = 120;
 
@@ -163,9 +161,6 @@ void DialDiscoverNowFunction::Work() {
 
 bool DialDiscoverNowFunction::Respond() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  if (!result_)
-    error_ = kDialServiceError;
-
   SetResult(new base::FundamentalValue(result_));
   return true;
 }

chrome/browser/extensions/api/dial/dial_apitest.cc

@@ -52,7 +52,6 @@ IN_PROC_BROWSER_TEST_F(DialAPITest, MAYBE_DeviceListEvents) {
   ASSERT_TRUE(api.get());
   extensions::DialRegistry::DeviceList devices;
 
-
   ResultCatcher catcher;
 
   DialDeviceData device1;
@@ -82,12 +81,17 @@ IN_PROC_BROWSER_TEST_F(DialAPITest, MAYBE_DeviceListEvents) {
   EXPECT_TRUE(catcher.GetNextResult()) << catcher.message();
 }
 
-// Test discoverNow fails if there are no listeners. When there are no listeners
-// the DIAL API will not be active.
 IN_PROC_BROWSER_TEST_F(DialAPITest, Discovery) {
   ASSERT_TRUE(RunExtensionSubtest("dial/experimental", "discovery.html"));
 }
 
+// discoverNow does not do discovery when there are no listeners; in that case
+// the DIAL service will not be active.
+IN_PROC_BROWSER_TEST_F(DialAPITest, DiscoveryNoListeners) {
+  ASSERT_TRUE(RunExtensionSubtest("dial/experimental",
+                                  "discovery_no_listeners.html"));
+}
+
 // Make sure this API is only accessible to whitelisted extensions.
 IN_PROC_BROWSER_TEST_F(DialAPITest, NonWhitelistedExtension) {
   ResultCatcher catcher;

chrome/test/data/extensions/api_test/dial/experimental/discovery.js

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Copyright (c) 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 onload = function() {
   chrome.test.runTests([
-    function discovery() {
-      var discoverNowShouldFail = function(result) {
-        if (!result) {
-          chrome.test.succeed();
-        } else {
-          chrome.test.fail();
-        }
+    function discoverySucceeds() {
+      var discoverNowCallback = function(result) {
+        chrome.test.assertNoLastError();
+        // The result may be true or false depending on whether periodic
+        // discovery is running at the same time.
+        // TODO(mfoltz): We may want to update the API to distinguish error cases
+        // from simultaneous discovery.
+        chrome.test.assertTrue(typeof(result) == 'boolean');
+        chrome.test.succeed();
       };
-      chrome.dial.discoverNow(discoverNowShouldFail);
+      chrome.dial.onDeviceList.addListener(function(deviceList) {});
+      chrome.dial.discoverNow(discoverNowCallback);
     }
   ]);
 };
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chrome/test/data/extensions/api_test/dial/experimental/discovery_no_listeners.html

+<script src="discovery_no_listeners.js"></script>
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chrome/test/data/extensions/api_test/dial/experimental/discovery_no_listeners.js

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+onload = function() {
+  chrome.test.runTests([
+    function discoverNowWithoutListeners() {
+      var discoverNowCallback = function(result) {
+        chrome.test.assertNoLastError();
+        chrome.test.assertTrue(typeof(result) == 'boolean');
+        if (!result) {
+          chrome.test.succeed();
+        } else {
+          chrome.test.fail();
+        }
+      };
+      chrome.dial.discoverNow(discoverNowCallback);
+    }
+  ]);
+};
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