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/linux/main_wnd.cc b/webrtc/examples/peerconnection/client/linux/main_wnd.cc
index 254fb94..cf98c1c 100644
--- a/webrtc/examples/peerconnection/client/linux/main_wnd.cc
+++ b/webrtc/examples/peerconnection/client/linux/main_wnd.cc
@@ -116,7 +116,8 @@
   wnd->OnRedraw();
   return false;
 }
-}  // end anonymous
+
+}  // namespace
 
 //
 // GtkMainWnd implementation.
@@ -174,7 +175,8 @@
   local_renderer_.reset();
 }
 
-void GtkMainWnd::StartRemoteRenderer(webrtc::VideoTrackInterface* remote_video) {
+void GtkMainWnd::StartRemoteRenderer(
+    webrtc::VideoTrackInterface* remote_video) {
   remote_renderer_.reset(new VideoRenderer(this, remote_video));
 }
 
@@ -488,7 +490,7 @@
           static_cast<int>(frame->GetHeight()));
 
   int size = width_ * height_ * 4;
-  // TODO: Convert directly to RGBA
+  // TODO(henrike): Convert directly to RGBA
   frame->ConvertToRgbBuffer(cricket::FOURCC_ARGB,
                             image_.get(),
                             size,