Add warning message for empty robustness.

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

 // Copyright 2014 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.
 
 #include "config.h"
 #include "modules/encryptedmedia/NavigatorRequestMediaKeySystemAccess.h"
 
 #include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "bindings/core/v8/ScriptState.h"
 #include "core/dom/DOMException.h"
 #include "core/dom/Document.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/frame/OriginsUsingFeatures.h"
 #include "core/frame/UseCounter.h"
+#include "core/inspector/ConsoleMessage.h"
 #include "modules/encryptedmedia/EncryptedMediaUtils.h"
 #include "modules/encryptedmedia/MediaKeySession.h"
 #include "modules/encryptedmedia/MediaKeySystemAccess.h"
 #include "modules/encryptedmedia/MediaKeysController.h"
 #include "platform/EncryptedMediaRequest.h"
 #include "platform/Logging.h"
 #include "platform/network/ParsedContentType.h"
+#include "public/platform/Platform.h"
 #include "public/platform/WebEncryptedMediaClient.h"
 #include "public/platform/WebEncryptedMediaRequest.h"
 #include "public/platform/WebMediaKeySystemConfiguration.h"
 #include "public/platform/WebMediaKeySystemMediaCapability.h"
 #include "public/platform/WebVector.h"
 #include "wtf/Vector.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
@@ skipping 103 matching lines @@
         if (config.hasSessionTypes()) {
             webConfig.hasSessionTypes = true;
             webConfig.sessionTypes = convertSessionTypes(config.sessionTypes());
         }
         // If |label| is not present, it will be a null string.
         webConfig.label = config.label();
         m_supportedConfigurations[i] = webConfig;
     }
 }
 
 void MediaKeySystemAccessInitializer::requestSucceeded(WebContentDecryptionModuleAccess* access)

[ddorwin, 2015/10/01 23:16:36]

Since we're not checking whether any were selected, we could do this in RMKSA?
That would also be a little more useful to the developer since the message
should be associated with the call.

Is there a reason we wouldn't want to report this for an unsupported
configuration?

If we move it, we might need to cycle through multiple configurations.

[xhwang, 2015/10/02 00:20:37]

From the email discussion, I thought we want to limit the noise as much as
possible. That why we choose to warn on the returned configuration.
Moved.

 {
+    // For widevine key system, generate warning and report to UMA if the
+    // returned config contains video capabilities with empty robustness string.
+    // TODO(xhwang): Remove after we handle empty robustness correctly.
+    // See http://crbug.com/482277
+    if (keySystem() == "com.widevine.alpha") {
+        WebMediaKeySystemConfiguration config = access->getConfiguration();
+        bool hasEmptyRobustness = false;
+
+        for (const auto& capability : config.videoCapabilities) {
+            if (capability.robustness.isEmpty())
+                hasEmptyRobustness = true;
+            Platform::current()->histogramEnumeration("Media.EME.Widevine.VideoCapability.EmptyRobustness", capability.robustness.isEmpty(), 2);

[ddorwin, 2015/10/01 23:16:36]

Similarly, HasEmptyRobustness as the UMA name?

The first comment might change the name as well.

[ddorwin, 2015/10/01 23:16:36]

We're recording every entry. Is that what we want? Don't we just want to know
the result of hasEmptyRobustness after the loop and record that?

[xhwang, 2015/10/02 00:20:37]

Done.

[xhwang, 2015/10/02 00:20:37]

Done.

+        }
+
+        if (hasEmptyRobustness) {
+            m_resolver->executionContext()->addConsoleMessage(ConsoleMessage::create(JSMessageSource, WarningMessageLevel,
+                "It is recommended that a robustness level be specified. Not specifying the robustness level could "
+                "result in unexpected behavior in the future, potentially including failure to play."));
+        }
+    }
+
     m_resolver->resolve(new MediaKeySystemAccess(m_keySystem, adoptPtr(access)));
     m_resolver.clear();
 }
 
 void MediaKeySystemAccessInitializer::requestNotSupported(const WebString& errorMessage)
 {
     m_resolver->reject(DOMException::create(NotSupportedError, errorMessage));
     m_resolver.clear();
 }
 
@@ skipping 53 matching lines @@
     //    initialize the MediaKeySystemAccess object.
     MediaKeysController* controller = MediaKeysController::from(document->page());
     WebEncryptedMediaClient* mediaClient = controller->encryptedMediaClient(executionContext);
     mediaClient->requestMediaKeySystemAccess(WebEncryptedMediaRequest(initializer));
 
     // 8. Return promise.
     return promise;
 }
 
 } // namespace blink