Mojo JS bindings: make sure that console.log() could be used in the bindings.

ios/web/webui/mojo_facade.mm

Index: ios/web/webui/mojo_facade.mm
diff --git a/ios/web/webui/mojo_facade.mm b/ios/web/webui/mojo_facade.mm
index bc9b59e031c2fcde9e4a435161377f1c902ad5d8..4300a1b0a45ddaf285944d19568e92eb395d69b3 100644
--- a/ios/web/webui/mojo_facade.mm
+++ b/ios/web/webui/mojo_facade.mm
@@ -9,6 +9,7 @@
 #import "base/ios/block_types.h"
 #include "base/json/json_reader.h"
 #include "base/json/json_writer.h"
+#include "base/logging.h"
 #import "base/mac/bind_objc_block.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/values.h"
@@ -70,6 +71,8 @@ std::string MojoFacade::HandleMojoMessage(
     result = HandleSupportWatch(args.get());
   } else if (name == "support.cancelWatch") {
     result = HandleSupportCancelWatch(args.get());
+  } else if (name == "console.log") {
+    result = HandleConsoleLog(args.get());
   }
 
   if (!result) {
@@ -270,4 +273,12 @@ std::unique_ptr<base::Value> MojoFacade::HandleSupportCancelWatch(
   return nullptr;
 }
 
+std::unique_ptr<base::Value> MojoFacade::HandleConsoleLog(
+    const base::DictionaryValue* args) {
+  std::string message;
+  CHECK(args->GetString("message", &message));
+  LOG(INFO) << message;
+  return nullptr;
+}
+
 }  // namespace web