[Presentation API] Add support to content/ for multiple URLs per PresentationRequest.

third_party/WebKit/public/platform/modules/presentation/WebPresentationClient.h

 // Copyright 2015 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.
 
 #ifndef WebPresentationClient_h
 #define WebPresentationClient_h
 
 #include "public/platform/WebCallbacks.h"
 #include "public/platform/WebCommon.h"
 
 #include <memory>
 
 namespace blink {
 
 class WebPresentationAvailabilityObserver;
 class WebPresentationController;
 class WebPresentationConnectionClient;
 class WebString;
 struct WebPresentationError;
+template <typename T>
+class WebVector;
 
 // If session was created, callback's onSuccess() is invoked with the information about the
 // presentation session created by the embedder. Otherwise, onError() is invoked with the error code
 // and message.
 using WebPresentationConnectionClientCallbacks = WebCallbacks<std::unique_ptr<WebPresentationConnectionClient>, const WebPresentationError&>;
 
 // Callback for .getAvailability().
 using WebPresentationAvailabilityCallbacks = WebCallbacks<bool, const WebPresentationError&>;
 
 // The implementation the embedder has to provide for the Presentation API to work.
 class WebPresentationClient {
 public:
     virtual ~WebPresentationClient() { }
 
     // Passes the Blink-side delegate to the embedder.
     virtual void setController(WebPresentationController*) = 0;
 
     // Called when the frame requests to start a new session.
     // The ownership of the |callbacks| argument is transferred to the embedder.
-    virtual void startSession(const WebString& presentationUrl, WebPresentationConnectionClientCallbacks*) = 0;
+    virtual void startSession(const WebVector<WebString>& presentationUrls, WebPresentationConnectionClientCallbacks*) = 0;

[dcheng, 2016/08/24 22:14:19]

These should be WebURLs as well, no?

[mark a. foltz, 2016/08/24 22:37:11]

We have dozens of files/APIs that need to be changed from string types to KURL,
WebURL, GURL, etc. and sweeping (if mechanical) type changes up and down the
stack is not the purpose of this patch.  This sort of change can be handled in a
separate patch that updates our code in Blink to use KURL/WebString.

We need to add multiple URL support to implement the current Presentation API
spec which is currently in CR.

[dcheng, 2016/08/24 23:12:17]

Can someone commit to doing this in an immediate followup? It's unfortunate this
was missed until now, but we really should be using richer types to describe
data when possible. That we have to write code like this:

 269   std::vector<std::string> presentation_urls_for_delegate(
 270       presentation_urls.size());
 271   std::transform(presentation_urls.begin(), presentation_urls.end(),
 272                  presentation_urls_for_delegate.begin(),
 273                  [](const url::mojom::UrlPtr& url) { return url->url; });

is quite unfortunate.

[mark a. foltz, 2016/08/29 23:54:54]

Added TODO for WebString -> WebURL conversion.

 
     // Called when the frame requests to join an existing session.
     // The ownership of the |callbacks| argument is transferred to the embedder.
-    virtual void joinSession(const WebString& presentationUrl, const WebString& presentationId, WebPresentationConnectionClientCallbacks*) = 0;
+    virtual void joinSession(const WebVector<WebString>& presentationUrls, const WebString& presentationId, WebPresentationConnectionClientCallbacks*) = 0;
 
     // Called when the frame requests to send String message to an existing session.
     virtual void sendString(const WebString& presentationUrl, const WebString& presentationId, const WebString& message) = 0;
 
     // Called when the frame requests to send ArrayBuffer/View data to an existing session.
     // Embedder copies the |data| and the ownership is not transferred.
     virtual void sendArrayBuffer(const WebString& presentationUrl, const WebString& presentationId, const uint8_t* data, size_t length) = 0;
 
     // Called when the frame requests to send Blob data to an existing session.
     // Embedder copies the |data| and the ownership is not transferred.
@@ skipping 14 matching lines @@
     // observer will be notified in case of a change. The observer is
     // respensible to call stopListening() before being destroyed.
     virtual void startListening(WebPresentationAvailabilityObserver*) = 0;
 
     // Stop listening to changes in presentation displays availability. The
     // observer will no longer be notified in case of a change.
     virtual void stopListening(WebPresentationAvailabilityObserver*) = 0;
 
     // Called when a defaultRequest has been set. It sends the url associated
     // with it for the embedder.
-    virtual void setDefaultPresentationUrl(const WebString&) = 0;
+    virtual void setDefaultPresentationUrls(const WebVector<WebString>&) = 0;
 };
 
 } // namespace blink
 
 #endif // WebPresentationClient_h