[PresentationAPI] Added/changed public/platform interfaces for start/joinSession

public/platform/modules/presentation/WebPresentationError.h

Index: public/platform/modules/presentation/WebPresentationError.h
diff --git a/public/platform/modules/presentation/WebPresentationError.h b/public/platform/modules/presentation/WebPresentationError.h
new file mode 100644
index 0000000000000000000000000000000000000000..58a84e6620f4dbcf24028b400b19ad57988cca4a
--- /dev/null
+++ b/public/platform/modules/presentation/WebPresentationError.h
@@ -0,0 +1,41 @@
+// 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 WebPresentationError_h
+#define WebPresentationError_h
+
+#include "public/platform/WebString.h"
+
+namespace blink {
+
+struct WebPresentationError {
+    enum ErrorType {
+        ErrorTypeNoAvailableScreens = 0,
+        ErrorTypeSessionRequestCancelled,
+        ErrorTypeNoPresentationFound,
+        ErrorTypeUnknown,
+        ErrorTypeLast = ErrorTypeUnknown
+    };
+
+    WebPresentationError(ErrorType errorType, const WebString& message)
+        : errorType(errorType)
+        , message(message)
+    {
+    }
+
+    WebPresentationError(int errorType, const WebString& message)

[mlamouri (slow - plz ping), 2015/02/23 13:58:53]

I think you should get ride of that constructor. Consumers of the public Blink
API should not pass random integers.

[whywhat, 2015/02/25 11:39:49]

Done.

+        : errorType(ErrorTypeUnknown)
+        , message(message)
+    {
+        if (errorType >= 0 && errorType <= ErrorTypeLast)
+            this->errorType = static_cast<ErrorType>(errorType);
+    }
+
+    ErrorType errorType;
+    WebString message;
+};
+
+} // namespace blink
+
+#endif // WebPresentationError_h