[eme] Enable checking of 'cbcs' support in Widevine

Recent versions of Widevine support 'cbcs' encrypted files, so add a query
test to verify that it is supported. As well, on systems where Widevine is
not component updated, indicate that the bundled Widevine does support
'cbcs' decryption.

BUG=835009
TEST=new browser_tests pass

Change-Id: Icc4294cca4ac9ba97c2a22816217c57e2262d30a
Reviewed-on: https://chromium-review.googlesource.com/1101405Reviewed-by: Xiaohan Wang <xhwang@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: John Rummell <jrummell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567433}

chrome/browser/media/encrypted_media_supported_types_browsertest.cc

@@ -1062,6 +1062,24 @@ IN_PROC_BROWSER_TEST_F(EncryptedMediaSupportedTypesWidevineTest, Robustness) {
 #endif
 }
 
+IN_PROC_BROWSER_TEST_F(EncryptedMediaSupportedTypesWidevineTest,
+                       EncryptionScheme) {
+  EXPECT_WV_SUCCESS(IsAudioEncryptionSchemeSupported(kWidevine, nullptr));
+  EXPECT_WV_SUCCESS(IsAudioEncryptionSchemeSupported(kWidevine, "cenc"));
+  EXPECT_WV_SUCCESS(IsAudioEncryptionSchemeSupported(kWidevine, "cbcs"));
+  EXPECT_WV_SUCCESS(IsVideoEncryptionSchemeSupported(kWidevine, nullptr));
+  EXPECT_WV_SUCCESS(IsVideoEncryptionSchemeSupported(kWidevine, "cenc"));
+  EXPECT_WV_SUCCESS(IsVideoEncryptionSchemeSupported(kWidevine, "cbcs"));
+
+  // Invalid encryption schemes will be rejected. However, invalid values
+  // generate a TypeError (The provided value '...' is not a valid enum value
+  // of type EncryptionScheme), which is not handled by the test page.
+  EXPECT_TYPEERROR(IsAudioEncryptionSchemeSupported(kWidevine, "Invalid"));
+  EXPECT_TYPEERROR(IsVideoEncryptionSchemeSupported(kWidevine, "Invalid"));
+  EXPECT_TYPEERROR(IsAudioEncryptionSchemeSupported(kWidevine, ""));
+  EXPECT_TYPEERROR(IsVideoEncryptionSchemeSupported(kWidevine, ""));
+}
+
 //
 // Misc failure test cases.
 //

chrome/common/chrome_content_client.cc

@@ -162,9 +162,11 @@ bool IsWidevineAvailable(
       *supports_persistent_license = false;
 #endif  // defined(OS_CHROMEOS)
 
-      // TODO(crbug.com/835009): Update once Widevine on Linux supports more
-      // encryption schemes.
+      // Add the supported encryption schemes as if they came from the
+      // component manifest. This list must match the CDM that is being
+      // bundled with Chrome.
       modes_supported->insert(media::EncryptionMode::kCenc);
+      modes_supported->insert(media::EncryptionMode::kCbcs);
 
       return true;
     }