Enable cpplint for webrtc/examples and fix all uncovered cpplint errors.

BUG=webrtc:5273
TESTED=Fixed issues reported by:
find webrtc/examples/ -type f -name *.cc -o -name *.h | grep -v objc | xargs cpplint.py
followed by 'git cl presubmit'.

NOTRY=True

Review URL: https://codereview.webrtc.org/1504283004

Cr-Commit-Position: refs/heads/master@{#10960}
diff --git a/webrtc/examples/peerconnection/client/defaults.cc b/webrtc/examples/peerconnection/client/defaults.cc
index f70aa72..a2501c7 100644
--- a/webrtc/examples/peerconnection/client/defaults.cc
+++ b/webrtc/examples/peerconnection/client/defaults.cc
@@ -50,10 +50,12 @@
 
 std::string GetPeerName() {
   char computer_name[256];
-  if (gethostname(computer_name, arraysize(computer_name)) != 0)
-    strcpy(computer_name, "host");
   std::string ret(GetEnvVarOrDefault("USERNAME", "user"));
   ret += '@';
-  ret += computer_name;
+  if (gethostname(computer_name, arraysize(computer_name)) == 0) {
+    ret += computer_name;
+  } else {
+    ret += "host";
+  }
   return ret;
 }