Build fix in protected_media_identifier_permission_context.cc

Build failed due to uninitialied values.
../../chrome/browser/media/protected_media_identifier_permission_context.cc:187:8: error: 'persist' may be used uninitialized in this function [-Werror=maybe-uninitialized]
../../chrome/browser/media/protected_media_identifier_permission_context.cc:205:32: error: 'content_setting' may be used uninitialized in this function [-Werror=maybe-uninitialized]

Review URL: https://codereview.chromium.org/974223002

Cr-Commit-Position: refs/heads/master@{#319088}

chrome/browser/media/protected_media_identifier_permission_context.cc

@@ -183,8 +183,8 @@ void ProtectedMediaIdentifierPermissionContext::OnPlatformVerificationResult(
   DCHECK(request->second.second.Equals(id));
   pending_requests_.erase(request);
 
-  ContentSetting content_setting;
-  bool persist; // Whether the ContentSetting should be saved.
+  ContentSetting content_setting = CONTENT_SETTING_DEFAULT;
+  bool persist = false; // Whether the ContentSetting should be saved.
   switch (response) {
     case PlatformVerificationFlow::CONSENT_RESPONSE_NONE:
       content_setting = CONTENT_SETTING_DEFAULT;