base: Remove the string logging from CHECK().

content/common/sandbox_linux/sandbox_linux.cc

Index: content/common/sandbox_linux/sandbox_linux.cc
diff --git a/content/common/sandbox_linux/sandbox_linux.cc b/content/common/sandbox_linux/sandbox_linux.cc
index 9823b2020f447b4327c981aa4c1cc01e869b6284..326feb62a038da0539705476a76a965798f744b2 100644
--- a/content/common/sandbox_linux/sandbox_linux.cc
+++ b/content/common/sandbox_linux/sandbox_linux.cc
@@ -254,8 +254,8 @@ int LinuxSandbox::GetStatus() {
 bool LinuxSandbox::IsSingleThreaded() const {
   base::ScopedFD proc_fd(OpenProc(proc_fd_));
 
-  CHECK(proc_fd.is_valid()) << "Could not count threads, the sandbox was not "
-                            << "pre-initialized properly.";
+  // Could not count threads, the sandbox was not pre-initialized properly.
+  CHECK(proc_fd.is_valid());
 
   const bool is_single_threaded =
       sandbox::ThreadHelpers::IsSingleThreaded(proc_fd.get());