[Fetch] Request with GET/HEAD method cannot have body

LayoutTests/http/tests/serviceworker/resources/cache-add-worker.js

 importScripts('worker-testharness.js');
 importScripts('/resources/testharness-helpers.js');
 
 cache_test(function(cache) {
     return assert_promise_rejects(
       cache.add(),
       new TypeError(),
       'Cache.add should throw a TypeError when no arguments are given.');
   }, 'Cache.add called with no arguments');
 
 cache_test(function(cache) {
     return cache.add('simple.txt')
       .then(function(result) {
           assert_equals(result, undefined,
                         'Cache.add should resolve with undefined on success.');
         });
   }, 'Cache.add called with relative URL specified as a string');
 
 cache_test(function(cache) {
     return assert_promise_rejects(
       cache.add('javascript://this-is-not-http-mmkay'),
       'NetworkError',
       'Cache.add should throw a NetworkError for non-HTTP/HTTPS URLs.');
   }, 'Cache.add called with non-HTTP/HTTPS URL');
 
 cache_test(function(cache) {
-    var request = new Request('simple.txt', {body: 'Hello'});
+    var request = new Request('simple.txt', {method: 'POST', body: 'Hello'});
     return cache.add(request)
       .then(function(result) {
           assert_equals(result, undefined,
                         'Cache.add should resolve with undefined on success.');
         });
   }, 'Cache.add called with Request object');
 
 cache_test(function(cache) {
-    var request = new Request('simple.txt', {body: 'Hello'});
+    var request = new Request('simple.txt', {method: 'POST', body: 'Hello'});
     return request.text()
       .then(function() {
           assert_true(request.bodyUsed);
         })
       .then(function() {
           return assert_promise_rejects(
             cache.add(request),
             new TypeError(),
             'Cache.add with a Request object with a used body should reject ' +
             'with a TypeError.');
         });
   }, 'Cache.add called with Request object with a used body');
 
 cache_test(function(cache) {
-    var request = new Request('simple.txt', {body: 'Hello'});
+    var request = new Request('simple.txt', {method: 'POST', body: 'Hello'});
     return cache.add(request)
       .then(function(result) {
           assert_equals(result, undefined,
                         'Cache.add should resolve with undefined on success.');
         })
       .then(function() {
           return assert_promise_rejects(
             cache.add(request),
             new TypeError(),
             'Cache.add should throw TypeError if same request is added twice.');
@@ skipping 76 matching lines @@
   }, 'Cache.addAll with a mix of succeeding and failing requests');
 
 cache_test(function(cache) {
     var request = new Request('simple.txt');
     return assert_promise_rejects(
       cache.addAll([request, request]),
       new TypeError(),
       'Cache.addAll should throw TypeError if the same request is added ' +
       'twice.');
   }, 'Cache.addAll called with the same Request object specified twice');