Change MediaKeys.setServerCertificate() to return Promise<boolean>

third_party/WebKit/Source/modules/encryptedmedia/MediaKeys.cpp

Index: third_party/WebKit/Source/modules/encryptedmedia/MediaKeys.cpp
diff --git a/third_party/WebKit/Source/modules/encryptedmedia/MediaKeys.cpp b/third_party/WebKit/Source/modules/encryptedmedia/MediaKeys.cpp
index 104fd8030bdaf676787d7b9d2eb61d806ebb266b..fb8f9d8a000e25e6e43dbdcc96a19565694cfb67 100644
--- a/third_party/WebKit/Source/modules/encryptedmedia/MediaKeys.cpp
+++ b/third_party/WebKit/Source/modules/encryptedmedia/MediaKeys.cpp
@@ -80,6 +80,33 @@ private:
     const Member<DOMArrayBuffer> m_data;
 };
 
+// This class wraps the promise resolver used when setting the certificate
+// and is passed to Chromium to fullfill the promise. This implementation of
+// complete() will resolve the promise with true, while completeWithError()
+// will reject the promise with an exception. completeWithSession()
+// is not expected to be called, and will reject the promise.
+class SetCertificateResultPromise : public ContentDecryptionModuleResultPromise {
+public:
+    SetCertificateResultPromise(ScriptState* scriptState)
+        : ContentDecryptionModuleResultPromise(scriptState)
+    {
+    }
+
+    ~SetCertificateResultPromise() override
+    {
+    }
+
+    // ContentDecryptionModuleResult implementation.
+    void complete() override
+    {
+        // TODO(jrummell): The EME spec specifies that "If the Key System
+        // implementation does not support server certificates, return a
+        // promise resolved with false." Need to have chromium return a bool
+        // so that resolving with false is possible. http://crbug.com/618800.
+        resolve(true);

[xhwang, 2016/06/10 21:40:11]

Can we translate completeWithError(NOT_SUPPORTED_ERROR) to resolve(false)? Then
we don't need to really change chromium other than making sure the right
exception is used.

NOT_SUPPORTED_ERROR means "The operation is not supported", which seems
appropriate for this use:

https://www.w3.org/TR/dom/#notsupportederror

[jrummell, 2016/06/10 23:01:15]

Done. I checked all the calls for SetServerCertificate(), and the only one
rejecting with NOT_SUPPORTED_ERROR is in aes_decryptor, so it provides the
desired behavior without lots of changes on the Chromium side.

+    }
+};
+
 MediaKeys* MediaKeys::create(ExecutionContext* context, const WebVector<WebEncryptedMediaSessionType>& supportedSessionTypes, PassOwnPtr<WebContentDecryptionModule> cdm)
 {
     MediaKeys* mediaKeys = new MediaKeys(context, supportedSessionTypes, std::move(cdm));
@@ -155,7 +182,7 @@ ScriptPromise MediaKeys::setServerCertificate(ScriptState* scriptState, const DO
     DOMArrayBuffer* serverCertificateBuffer = DOMArrayBuffer::create(serverCertificate.data(), serverCertificate.byteLength());
 
     // 4. Let promise be a new promise.
-    SimpleContentDecryptionModuleResultPromise* result = new SimpleContentDecryptionModuleResultPromise(scriptState);
+    SetCertificateResultPromise* result = new SetCertificateResultPromise(scriptState);
     ScriptPromise promise = result->promise();
 
     // 5. Run the following steps asynchronously (documented in timerFired()).