Hide console log messages for imported WPT tests

content/shell/test_runner/web_frame_test_client.cc

Index: content/shell/test_runner/web_frame_test_client.cc
diff --git a/content/shell/test_runner/web_frame_test_client.cc b/content/shell/test_runner/web_frame_test_client.cc
index ac85df245e22584c5628b14d64a80034f98aec02..005dc39a98e81297924bfc031e770b78ca47250e 100644
--- a/content/shell/test_runner/web_frame_test_client.cc
+++ b/content/shell/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 "content/shell/test_runner/accessibility_controller.h"
@@ -648,10 +649,11 @@ 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);
   }
+  bool dump_to_stderr = test_runner()->is_web_platform_tests_mode();
   if (!message.text.isEmpty()) {
     std::string new_message;
     new_message = message.text.utf8();
@@ -660,9 +662,21 @@ void WebFrameTestClient::didAddMessageToConsole(
       new_message = new_message.substr(0, file_protocol) +
                     URLSuitableForTestResult(new_message.substr(file_protocol));
     }
-    delegate_->PrintMessage(new_message);
+    for (auto piece : base::SplitStringPieceUsingSubstr(
+             new_message, "\n", base::KEEP_WHITESPACE, base::SPLIT_WANT_ALL)) {
+      if (dump_to_stderr) {
+        delegate_->PrintLogMessage(prefix + piece.as_string() + "\n");
+      } else {
+        delegate_->PrintMessage(prefix + piece.as_string() + "\n");
+      }
+    }
+  } else {
+    if (dump_to_stderr) {
+      delegate_->PrintLogMessage(prefix + "\n");
+    } else {
+      delegate_->PrintMessage(prefix + "\n");
+    }
   }
-  delegate_->PrintMessage(std::string("\n"));
 }
 
 blink::WebNavigationPolicy WebFrameTestClient::decidePolicyForNavigation(