[ServiceWorker] Provide more descriptive error messages when fetch API fails.

LayoutTests/http/tests/serviceworker/resources/fetch-worker.js

 importScripts('worker-testharness.js');
 importScripts('test-helpers.js');
 
 async_test(function(t) {
     fetch('http://')
       .then(
         unreached_rejection(t, 'fetch of invalid URL must fail'),
         function(e) {
           assert_equals(e.message, 'Invalid URL');
           t.done();
@@ skipping 121 matching lines @@
           assert_equals(files['BlobKey'].name, 'blob');
           assert_equals(files['BlobKey'].size, 12);
           assert_equals(files['FileKey'].content, 'file content');
           assert_equals(files['FileKey'].name, 'file.dat');
           assert_equals(files['FileKey'].size, 12);
           t.done();
         })
       .catch(unreached_rejection(t));
   }, 'Fetch with FormData body test in ServiceWorkerGlobalScope');
 
+async_test(function(t) {
+    var url = get_host_info()['HTTP_REMOTE_ORIGIN'] + '/dymmy.html';

[falken, 2014/11/17 02:14:46]

nit: dummy

[horo, 2014/11/17 03:25:35]

Done.

+    fetch(new Request(url, {mode: 'same-origin'}))
+      .then(
+        unreached_rejection(t, 'Fetching must fail.'),
+        function(e) {
+          assert_equals(
+            e.message,
+            'Fetch API cannot load ' + url + '. ' +
+            'Request mode is "same-origin" but the URL is not same origin.');
+          t.done();
+        })
+      .catch(unreached_rejection(t));
+  }, 'Fetch API error message - not same origin request');
+
+async_test(function(t) {
+    var url = 'ftp://example.com/dummy.html';
+    fetch(new Request(url, {mode: 'cors'}))
+      .then(
+        unreached_rejection(t, 'Fetching must fail.'),
+        function(e) {
+          assert_equals(
+            e.message,
+            'Fetch API cannot load ' + url + '. ' +
+            'URL scheme must be "http" or "https" for CORS request.');
+          t.done();
+        })
+      .catch(unreached_rejection(t));
+  }, 'Fetch API error message - non http cors request');
+
+async_test(function(t) {
+    var url = 'about://blank';
+    fetch(new Request(url))
+      .then(
+        unreached_rejection(t, 'Fetching must fail.'),
+        function(e) {
+          assert_equals(
+            e.message,
+            'Fetch API cannot load ' + url + '. ' +
+            'URL scheme "about" is not supported.');
+          t.done();
+        })
+      .catch(unreached_rejection(t));
+  }, 'Fetch API error message - unsupported scheme.');
+
+async_test(function(t) {
+    var url = get_host_info()['HTTP_ORIGIN'] + base_path() +
+              'invalid-chunked-encoding.php';
+    fetch(new Request(url))
+      .then(
+        unreached_rejection(t, 'Fetching must fail.'),
+        function(e) {
+          assert_equals(
+            e.message,
+            'Fetch API cannot load ' + url + '. ' +
+            'net::ERR_INVALID_CHUNKED_ENCODING');
+          t.done();
+        })
+      .catch(unreached_rejection(t));
+  }, 'Fetch API error message - invalid chunled encoding.');

[falken, 2014/11/17 02:14:46]

nit: chunked

[horo, 2014/11/17 03:25:35]

Done.

+
+async_test(function(t) {
+    var url = get_host_info()['HTTP_REMOTE_ORIGIN'] + base_path() +
+              'fetch-access-control.php';
+    fetch(new Request(url))
+      .then(
+        unreached_rejection(t, 'Fetching must fail.'),
+        function(e) {
+          assert_equals(
+            e.message,
+            'Fetch API cannot load ' + url + '. ' +
+            'No \'Access-Control-Allow-Origin\' header is present on the ' +
+            'requested resource. Origin \'' + get_host_info()['HTTP_ORIGIN'] +
+            '\' is therefore not allowed access.');
+          t.done();
+        })
+      .catch(unreached_rejection(t));
+  }, 'Fetch API error message - cors error.');
+
+async_test(function(t) {
+    // FIXME: When we support the redirection in Fech API, we have to change
+    // this test case.
+    var url = get_host_info()['HTTP_ORIGIN'] + base_path() +
+              'redirect.php?Redirect=http://www.example.com';
+    fetch(new Request(url))
+      .then(
+        unreached_rejection(t, 'Fetching must fail.'),
+        function(e) {
+          assert_equals(
+            e.message,
+            'Fetch API cannot load ' + url + '. ' +
+            'Unsupported redirection.');
+          t.done();
+        })
+      .catch(unreached_rejection(t));
+  }, 'Fetch API error message - redirect error.');
+
 test(function(t) {
     function runInfiniteFetchLoop() {
       fetch('dummy.html')
         .then(function() { runInfiniteFetchLoop(); });
     }
     runInfiniteFetchLoop();
   },
   'Destroying the execution context while fetch is happening should not ' +
   'cause a crash.');