Hide console log messages for imported WPT tests

components/test_runner/web_frame_test_client.cc

Index: components/test_runner/web_frame_test_client.cc
diff --git a/components/test_runner/web_frame_test_client.cc b/components/test_runner/web_frame_test_client.cc
index 11a8edae86f9ede7b05a9b0192646d2aa5d403b6..2dcaee2027f1f9f49d72e9896712e730fa6f249f 100644
--- a/components/test_runner/web_frame_test_client.cc
+++ b/components/test_runner/web_frame_test_client.cc
@@ -8,6 +8,7 @@
 
 #include "base/logging.h"
 #include "base/strings/string_piece.h"
+#include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "components/test_runner/accessibility_controller.h"
@@ -648,9 +649,9 @@ void WebFrameTestClient::didAddMessageToConsole(
     default:
       level = "MESSAGE";
   }
-  delegate_->PrintMessage(std::string("CONSOLE ") + level + ": ");
+  std::string prefix(std::string("CONSOLE ") + level + ": ");
   if (source_line) {
-    delegate_->PrintMessage(base::StringPrintf("line %d: ", source_line));
+    prefix += base::StringPrintf("line %d: ", source_line);
   }
   if (!message.text.isEmpty()) {
     std::string new_message;
@@ -660,9 +661,15 @@ void WebFrameTestClient::didAddMessageToConsole(
       new_message = new_message.substr(0, file_protocol) +
                     URLSuitableForTestResult(new_message.substr(file_protocol));
     }
-    delegate_->PrintMessage(new_message);
+    for (auto s : base::SplitStringPieceUsingSubstr(
+             new_message, "\n", base::KEEP_WHITESPACE, base::SPLIT_WANT_ALL)) {
+      delegate_->PrintMessage(prefix);
+      delegate_->PrintMessage(s.as_string());
+      delegate_->PrintMessage(std::string("\n"));
+    }
+  } else {
+    delegate_->PrintMessage(prefix + "\n");
   }
-  delegate_->PrintMessage(std::string("\n"));
 }
 
 blink::WebNavigationPolicy WebFrameTestClient::decidePolicyForNavigation(