Rename requireUserMediation to preventSilentAccess in the CM API.

third_party/WebKit/Source/core/frame/Deprecation.cpp

Index: third_party/WebKit/Source/core/frame/Deprecation.cpp
diff --git a/third_party/WebKit/Source/core/frame/Deprecation.cpp b/third_party/WebKit/Source/core/frame/Deprecation.cpp
index 0499bd8a40f5638ac11bcea5e7f31fe8159c0fa7..0442e3c9be0df1a3ea267c0f467e7237780d32ad 100644
--- a/third_party/WebKit/Source/core/frame/Deprecation.cpp
+++ b/third_party/WebKit/Source/core/frame/Deprecation.cpp
@@ -425,6 +425,12 @@ String Deprecation::DeprecationMessage(UseCounter::Feature feature) {
           "recent-changes-credential-management-api for migration suggestions.",
           milestoneString(M62));
 
+    case UseCounter::kCredentialManagerRequireUserMediation:
+      return String::Format(
+          "'requireUserMediation' was renamed to 'preventSilentAccess'. The "
+          "method will be removed in %s.",
+          milestoneString(M62));

[Mike West, 2017/05/23 18:54:32]

Nit: I'd suggest something like:

```
return replacedWillBeRemoved(
    "The CredentialsContainer.requireUserMediation method",
    "the CredentialsContainer.preventSilentAccess method",
    M62,
    "4781762488041472");
```

[vasilii, 2017/05/24 10:02:13]

Done.

+
     // Features that aren't deprecated don't have a deprecation message.
     default:
       return String();