media: Add Feature to control External Clear Key key system support

chrome/browser/media/encrypted_media_supported_types_browsertest.cc

Index: chrome/browser/media/encrypted_media_supported_types_browsertest.cc
diff --git a/chrome/browser/media/encrypted_media_supported_types_browsertest.cc b/chrome/browser/media/encrypted_media_supported_types_browsertest.cc
index 91f10c52b94830820273eb0634946e26ca179c69..9fa7eb4c87335fccd9f97489253bc44a6e976193 100644
--- a/chrome/browser/media/encrypted_media_supported_types_browsertest.cc
+++ b/chrome/browser/media/encrypted_media_supported_types_browsertest.cc
@@ -286,10 +286,29 @@ class EncryptedMediaSupportedTypesExternalClearKeyTest
     RegisterPepperCdm(command_line, kClearKeyCdmBaseDirectory,
                       kClearKeyCdmAdapterFileName, kClearKeyCdmDisplayName,
                       kClearKeyCdmPepperMimeType);
+    command_line->AppendSwitchASCII(switches::kEnableFeatures,
+                                    media::kExternalClearKeyForTesting.name);
   }
 #endif  // defined(ENABLE_PEPPER_CDMS)
 };
 
+// By default, the External Clear Key (ECK) key system is not supported even if
+// present. This test case tests this behavior by not enabling
+// kExternalClearKeyForTesting.
+// Even registering the Pepper CDM where applicable does not enable the CDM.
+class EncryptedMediaSupportedTypesExternalClearKeyNotEnabledTest
+    : public EncryptedMediaSupportedTypesTest {
+ protected:
+  void SetUpCommandLine(base::CommandLine* command_line) override {
+    EncryptedMediaSupportedTypesTest::SetUpCommandLine(command_line);
+#if defined(ENABLE_PEPPER_CDMS)
+    RegisterPepperCdm(command_line, kClearKeyCdmBaseDirectory,
+                      kClearKeyCdmAdapterFileName, kClearKeyCdmDisplayName,
+                      kClearKeyCdmPepperMimeType);
+#endif  // defined(ENABLE_PEPPER_CDMS)
+  }
+};
+
 class EncryptedMediaSupportedTypesWidevineTest
     : public EncryptedMediaSupportedTypesTest {
 };
@@ -305,6 +324,8 @@ class EncryptedMediaSupportedTypesClearKeyCDMRegisteredWithWrongPathTest
                       "clearkeycdmadapterwrongname.dll",
                       kClearKeyCdmDisplayName, kClearKeyCdmPepperMimeType,
                       false);
+    command_line->AppendSwitchASCII(switches::kEnableFeatures,
+                                    media::kExternalClearKeyForTesting.name);
   }
 };
 
@@ -320,6 +341,7 @@ class EncryptedMediaSupportedTypesWidevineCDMRegisteredWithWrongPathTest
                       "application/x-ppapi-widevine-cdm", false);
   }
 };
+
 #endif  // defined(ENABLE_PEPPER_CDMS)
 
 IN_PROC_BROWSER_TEST_F(EncryptedMediaSupportedTypesClearKeyTest, Basic) {
@@ -574,6 +596,18 @@ IN_PROC_BROWSER_TEST_F(EncryptedMediaSupportedTypesExternalClearKeyTest,
       kAudioMP4MimeType, video_webm_codecs(), kExternalClearKey));
 }
 
+// External Clear Key is disabled by default.
+IN_PROC_BROWSER_TEST_F(
+    EncryptedMediaSupportedTypesExternalClearKeyNotEnabledTest,
+    Basic) {
+  EXPECT_UNKNOWN_KEYSYSTEM(AreCodecsSupportedByKeySystem(
+      kVideoWebMMimeType, no_codecs(), kExternalClearKey));
+
+  // Clear Key should still be registered.
+  EXPECT_SUCCESS(AreCodecsSupportedByKeySystem(kVideoWebMMimeType, no_codecs(),
+                                               kClearKey));
+}
+
 //
 // Widevine
 //