Move extension API schema registration to ExtensionsClient.

extensions/test/test_extensions_client.cc

Index: extensions/test/test_extensions_client.cc
diff --git a/extensions/test/test_extensions_client.cc b/extensions/test/test_extensions_client.cc
index 7ef0277da678fb727c16beb7ac2916a41e7ab92a..8cee49a19c25046dd71f08138847451721b42cb9 100644
--- a/extensions/test/test_extensions_client.cc
+++ b/extensions/test/test_extensions_client.cc
@@ -85,6 +85,9 @@ base::StringPiece TestExtensionsClient::GetAPISchema(
   return base::StringPiece();
 }
 
+void TestExtensionsClient::RegisterAPISchemaResources(ExtensionAPI* api) const {
+}
+
 bool TestExtensionsClient::ShouldSuppressFatalErrors() const {
   return true;
 }