EME: Correctly handle container-only contentType strings

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 "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/Deprecation.h"
 #include "core/frame/OriginsUsingFeatures.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/Histogram.h"
 #include "platform/Logging.h"
 #include "platform/network/ParsedContentType.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"
+#include <algorithm>
 
 namespace blink {
 
 namespace {
 
 static WebVector<WebEncryptedMediaInitDataType> convertInitDataTypes(const Vector<String>& initDataTypes)
 {
     WebVector<WebEncryptedMediaInitDataType> result(initDataTypes.size());
     for (size_t i = 0; i < initDataTypes.size(); ++i)
         result[i] = EncryptedMediaUtils::convertToInitDataType(initDataTypes[i]);
@@ skipping 32 matching lines @@
 }
 
 static WebVector<WebEncryptedMediaSessionType> convertSessionTypes(const Vector<String>& sessionTypes)
 {
     WebVector<WebEncryptedMediaSessionType> result(sessionTypes.size());
     for (size_t i = 0; i < sessionTypes.size(); ++i)
         result[i] = EncryptedMediaUtils::convertToSessionType(sessionTypes[i]);
     return result;
 }
 
+static bool AreCodecsSpecified(const WebMediaKeySystemMediaCapability& capability)
+{
+    return !capability.codecs.isEmpty();
+}
+
 // This class allows capabilities to be checked and a MediaKeySystemAccess
 // object to be created asynchronously.
 class MediaKeySystemAccessInitializer final : public EncryptedMediaRequest {
     WTF_MAKE_NONCOPYABLE(MediaKeySystemAccessInitializer);
 
 public:
     MediaKeySystemAccessInitializer(ScriptState*, const String& keySystem, const HeapVector<MediaKeySystemConfiguration>& supportedConfigurations);
     ~MediaKeySystemAccessInitializer() override { }
 
     // EncryptedMediaRequest implementation.
@@ skipping 12 matching lines @@
     }
 
 private:
     // For widevine key system, generate warning and report to UMA if
     // |m_supportedConfigurations| contains any video capability with empty
     // robustness string.
     // TODO(xhwang): Remove after we handle empty robustness correctly.
     // See http://crbug.com/482277
     void checkVideoCapabilityRobustness() const;
 
+    // Generate warning and report UMA if configuration contains a
+    // container-only contentType string.
+    // TODO(jrummell): Remove once this is no longer allowed.
+    // See http://crbug.com/605661.
+    void checkEmptyCodecs(const WebMediaKeySystemConfiguration&);
+
     Member<ScriptPromiseResolver> m_resolver;
     const String m_keySystem;
     WebVector<WebMediaKeySystemConfiguration> m_supportedConfigurations;
 };
 
 MediaKeySystemAccessInitializer::MediaKeySystemAccessInitializer(ScriptState* scriptState, const String& keySystem, const HeapVector<MediaKeySystemConfiguration>& supportedConfigurations)
     : m_resolver(ScriptPromiseResolver::create(scriptState))
     , m_keySystem(keySystem)
     , m_supportedConfigurations(supportedConfigurations.size())
 {
@@ skipping 23 matching lines @@
         // If |label| is not present, it will be a null string.
         webConfig.label = config.label();
         m_supportedConfigurations[i] = webConfig;
     }
 
     checkVideoCapabilityRobustness();
 }
 
 void MediaKeySystemAccessInitializer::requestSucceeded(WebContentDecryptionModuleAccess* access)
 {
+    checkEmptyCodecs(access->getConfiguration());
+
     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 28 matching lines @@
         emptyRobustnessHistogram.count(hasEmptyRobustness);
     }
 
     if (hasEmptyRobustness) {
         m_resolver->getExecutionContext()->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."));
     }
 }
 
+void MediaKeySystemAccessInitializer::checkEmptyCodecs(const WebMediaKeySystemConfiguration& config)
+{
+    // This is only checking for empty codecs in the selected configuration,
+    // as apps may pass container only contentType strings for compatibility
+    // with other implementations.
+    // This will only check that all returned capabilities do not contain
+    // codecs. This allows apps to provide both (one with codecs, one without)

[ddorwin, 2016/04/27 23:33:48]

Since we don't think this is useful, perhaps we should just say, "This avoids
alerting on configurations that will continue to succeed..."

[jrummell, 2016/04/28 01:32:47]

Done.

+    // for compatibility reasons, and that will continue to succeed in the
+    // future once strict checking is enforced.
+    bool areAllAudioCodecsEmpty = false;
+    if (config.hasAudioCapabilities && !config.audioCapabilities.isEmpty()) {
+        areAllAudioCodecsEmpty = std::find_if(config.audioCapabilities.begin(), config.audioCapabilities.end(), AreCodecsSpecified)
+            == config.audioCapabilities.end();

[jrummell, 2016/04/26 21:23:57]

Tried to split this into meaningful lines so that it's not one long line, but
this is all I can get "git clang-format --style Webkit", "git cl format", and
presubmit to agree on.

+
+        DEFINE_THREAD_SAFE_STATIC_LOCAL(EnumerationHistogram, emptyAudioCodecsHistogram,
+            new EnumerationHistogram("Media.EME.RequestMediaKeySystemAccess.SelectedAudioContentTypeWithoutCodecs", 2));

[ddorwin, 2016/04/27 23:33:48]

Hmm. This isn't strictly accurate since we are checking for _all_.

AllSelectedAudioContentTypeMisingCodecs?

[jrummell, 2016/04/28 01:32:47]

Switched to UseCounter.

+        emptyAudioCodecsHistogram.count(areAllAudioCodecsEmpty);
+    }
+
+    bool areAllVideoCodecsEmpty = false;
+    if (config.hasVideoCapabilities && !config.videoCapabilities.isEmpty()) {
+        areAllVideoCodecsEmpty = std::find_if(config.videoCapabilities.begin(), config.videoCapabilities.end(), AreCodecsSpecified)
+            == config.videoCapabilities.end();
+
+        DEFINE_THREAD_SAFE_STATIC_LOCAL(EnumerationHistogram, emptyVideoCodecsHistogram,
+            new EnumerationHistogram("Media.EME.RequestMediaKeySystemAccess.SelectedVideoContentTypeWithoutCodecs", 2));
+        emptyVideoCodecsHistogram.count(areAllVideoCodecsEmpty);
+    }
+
+    if (areAllAudioCodecsEmpty || areAllVideoCodecsEmpty) {
+        m_resolver->getExecutionContext()->addConsoleMessage(ConsoleMessage::create(JSMessageSource, WarningMessageLevel,

[ddorwin, 2016/04/27 23:33:48]

Should we use countDeprecation() instead of a separate histogram? UseCounter
isn't as easy to use as our own histogram, but it does deal with logging
consistently.

[jrummell, 2016/04/28 01:32:47]

Done (along with counting the successes).

+            "contentType strings without codecs will not be supported in the future."
+            "Please specify the desired codec(s) as part of the contentType."));
+    }
+}
+
 } // namespace
 
 ScriptPromise NavigatorRequestMediaKeySystemAccess::requestMediaKeySystemAccess(
     ScriptState* scriptState,
     Navigator& navigator,
     const String& keySystem,
     const HeapVector<MediaKeySystemConfiguration>& supportedConfigurations)
 {
     WTF_LOG(Media, "NavigatorRequestMediaKeySystemAccess::requestMediaKeySystemAccess()");
 
@@ skipping 42 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