Introduce "navigate" mode in Requests

third_party/WebKit/Source/modules/fetch/Request.cpp

Index: third_party/WebKit/Source/modules/fetch/Request.cpp
diff --git a/third_party/WebKit/Source/modules/fetch/Request.cpp b/third_party/WebKit/Source/modules/fetch/Request.cpp
index 5db7648fc618dc5a97b6b56c8e60dc2fd44edc7b..3189fd5552e3bff89f7b1060d4f8fdc12d3caad3 100644
--- a/third_party/WebKit/Source/modules/fetch/Request.cpp
+++ b/third_party/WebKit/Source/modules/fetch/Request.cpp
@@ -120,15 +120,23 @@ Request* Request::createRequestWithRequestOrString(ScriptState* scriptState, Req
         // We don't use fallback values. We set these flags directly in below.
     }
 
-    //   14. If any of |init|'s members are present, set |request|'s referrer
-    // to client, and |request|'s referrer policy to the empty string.
-    //   => RequestInit::RequestInit.
+    // "14. If any of |init|'s members are present, run these substeps:"
+    if (init.areAnyMembersSet) {
+        // "1. If request's |mode| is "navigate", throw a TypeError."
+        if (request->mode() == WebURLRequest::FetchRequestModeNavigate) {
+            exceptionState.throwTypeError("Cannot construct a Request with a Request mode as navigate.");

[hiroshige, 2015/10/30 12:31:30]

Making the message here and L177 will be better.

(I don't have good sentences though...
"Cannot construct a Request from a Request with 'navigate' mode and RequestInit"
and
"Mode 'navigate' cannot be specified in Request constructor"?
Not so good though...)

[shiva.jm, 2015/11/02 12:06:20]

Done.

+            return nullptr;
+        }
+    }
+
     //   15. If |init|'s referrer member is present, run these substeps:
     // Note that JS null and undefined are encoded as an empty string and thus
     // a null string means referrer member is not set.
     //   16. If |init|'s referrerPolicy member is present, set |request|'s
     // referrer policy to it.
-    if (init.isReferrerSet) {
+    // areAnyMembersSet will be True, if any members in RequestInit are set and

[hiroshige, 2015/10/30 12:31:30]

nit: This comment (L137-138) is not needed.

IIUC "if (init.areAnyMembersSet)" is used in L139 (rather than checking |init|'s
referrer member) to implement the following spec statement:
If |init|'s referrer member is not present, then |request|'s referrer is set to
"client" via the default value set in |init.referrer| in RequestInit.
yhirano@, is this correct?

[yhirano, 2015/10/30 13:18:41]

- If no member is set on |init| => use |request|'s referrer.
- Elif "referrer" member is present => use that value.
- Else => use "client".

In Blink, RequestInit::RequestInit implements part of the logic and I think
mentioning that would be helpful. That's why I added the comment  at L125 in the
original code.

[shiva.jm, 2015/11/02 12:06:20]

These comment is needed, as discussed in:
https://codereview.chromium.org/1391583002/#msg14

[shiva.jm, 2015/11/02 12:06:20]

Done, retained old comment, after line 129 in new code,
will make code changes for these in next CL ( i.e to set
request's referrer to "client" and referrer policy to the empty string).
I think "no member is set on |init|", is handled as default case?

+    // hence the referrer member
+    if (init.areAnyMembersSet) {
         // 1. Let |referrer| be |init|'s referrer member.
         if (init.referrer.referrer.isEmpty()) {
             // 2. if |referrer| is the empty string, set |request|'s referrer to
@@ -161,10 +169,14 @@ Request* Request::createRequestWithRequestOrString(ScriptState* scriptState, Req
         request->setReferrerPolicy(init.referrer.referrerPolicy);
     }
 
-
-    // "17. Let |mode| be |init|'s mode member if it is present, and
+    // "16. Let |mode| be |init|'s mode member if it is present, and
     // |fallbackMode| otherwise."
+    // "17.If mode is "navigate", throw a TypeError.

[hiroshige, 2015/10/30 12:31:30]

nit: a space between "17." and "If".

[shiva.jm, 2015/11/02 12:06:20]

Done.

     // "18. If |mode| is non-null, set |request|'s mode to |mode|."
+    if (init.mode == "navigate") {
+        exceptionState.throwTypeError("Cannot construct a Request with a Request mode as navigate.");
+        return nullptr;
+    }
     if (init.mode == "same-origin") {
         request->setMode(WebURLRequest::FetchRequestModeSameOrigin);
     } else if (init.mode == "no-cors") {
@@ -497,6 +509,8 @@ String Request::mode() const
     case WebURLRequest::FetchRequestModeCORS:
     case WebURLRequest::FetchRequestModeCORSWithForcedPreflight:
         return "cors";
+    case WebURLRequest::FetchRequestModeNavigate:
+        return "navigate";
     }
     ASSERT_NOT_REACHED();
     return "";