Bug 1846848 - part6 : display GMPCDM capabilities in about:support. r=jolin

ClearKey and Widevine L3 are used in the GMP process, so comparing with
MFCDM, we need to use another different way to access their capabilities.

Differential Revision: https://phabricator.services.mozilla.com/D194932

dom/base/ChromeUtils.cpp

@@ -1944,4 +1944,17 @@ already_AddRefed<Promise> ChromeUtils::GetWMFContentDecryptionModuleInformation(
 }
 #endif
 
+already_AddRefed<Promise> ChromeUtils::GetGMPContentDecryptionModuleInformation(
+    GlobalObject& aGlobal, ErrorResult& aRv) {
+  nsCOMPtr<nsIGlobalObject> global = do_QueryInterface(aGlobal.GetAsSupports());
+  MOZ_ASSERT(global);
+  RefPtr<Promise> domPromise = Promise::Create(global, aRv);
+  if (NS_WARN_IF(aRv.Failed())) {
+    return nullptr;
+  }
+  MOZ_ASSERT(domPromise);
+  KeySystemConfig::GetGMPKeySystemConfigs(domPromise);
+  return domPromise.forget();
+}
+
 }  // namespace mozilla::dom

dom/base/ChromeUtils.h

@@ -313,6 +313,9 @@ class ChromeUtils {
       GlobalObject& aGlobal, ErrorResult& aRv);
 #endif
 
+  static already_AddRefed<Promise> GetGMPContentDecryptionModuleInformation(
+      GlobalObject& aGlobal, ErrorResult& aRv);
+
  private:
   // Number of DevTools session debugging the current process
   static std::atomic<uint32_t> sDevToolsOpenedCount;

dom/chrome-webidl/ChromeUtils.webidl

@@ -306,6 +306,13 @@ namespace ChromeUtils {
   Promise<sequence<CDMInformation>> getWMFContentDecryptionModuleInformation();
 #endif
 
+  /**
+   * Returns the information about the GMP based content decryption
+   * modules, which would include key system names and their capabilities.
+   */
+  [NewObject]
+  Promise<sequence<CDMInformation>> getGMPContentDecryptionModuleInformation();
+
   /**
    * IF YOU ADD NEW METHODS HERE, MAKE SURE THEY ARE THREAD-SAFE.
    */

dom/media/eme/KeySystemConfig.cpp

@@ -211,6 +211,30 @@ bool KeySystemConfig::IsSameKeySystem(const nsAString& aKeySystem) const {
   return mKeySystem.Equals(aKeySystem);
 }
 
+/* static */
+void KeySystemConfig::GetGMPKeySystemConfigs(dom::Promise* aPromise) {
+  MOZ_ASSERT(aPromise);
+  nsTArray<KeySystemConfig> keySystemConfigs;
+  const nsTArray<nsString> keySystemNames{
+      NS_ConvertUTF8toUTF16(kClearKeyKeySystemName),
+      NS_ConvertUTF8toUTF16(kWidevineKeySystemName),
+  };
+  FallibleTArray<dom::CDMInformation> cdmInfo;
+  for (const auto& name : keySystemNames) {
+    if (KeySystemConfig::CreateKeySystemConfigs(name, keySystemConfigs)) {
+      auto* info = cdmInfo.AppendElement(fallible);
+      if (!info) {
+        aPromise->MaybeReject(NS_ERROR_OUT_OF_MEMORY);
+        return;
+      }
+      MOZ_ASSERT(keySystemConfigs.Length() == cdmInfo.Length());
+      info->mKeySystemName = name;
+      info->mCapabilities = keySystemConfigs.LastElement().GetDebugInfo();
+    }
+  }
+  aPromise->MaybeResolve(cdmInfo);
+}
+
 nsString KeySystemConfig::GetDebugInfo() const {
   nsString debugInfo;
   debugInfo.AppendLiteral(" key-system=");

dom/media/eme/KeySystemConfig.h

@@ -124,6 +124,7 @@ struct KeySystemConfig {
   static bool Supports(const nsAString& aKeySystem);
   static bool CreateKeySystemConfigs(const nsAString& aKeySystem,
                                      nsTArray<KeySystemConfig>& aOutConfigs);
+  static void GetGMPKeySystemConfigs(dom::Promise* aPromise);
 
   KeySystemConfig() = default;
   ~KeySystemConfig() = default;

toolkit/content/aboutSupport.js

@@ -1182,10 +1182,15 @@ var snapshotFormatters = {
 
     async function insertContentDecryptionModuleInfo() {
       let rows = [];
+      // Retrieve information from GMPCDM
+      let cdmInfo =
+        await ChromeUtils.getGMPContentDecryptionModuleInformation();
+      for (let info of cdmInfo) {
+        rows.push(createCDMInfoRow(info));
+      }
       // Retrieve information from WMFCDM, only works when MOZ_WMF_CDM is true
       if (ChromeUtils.getWMFContentDecryptionModuleInformation !== undefined) {
-        const cdmInfo =
-          await ChromeUtils.getWMFContentDecryptionModuleInformation();
+        cdmInfo = await ChromeUtils.getWMFContentDecryptionModuleInformation();
         for (let info of cdmInfo) {
           rows.push(createCDMInfoRow(info));
         }