title: customizing gyp and gypi files of chromium source code to add a new file
body: <p>I am new to chromium source code. I have few doubt regarding chromium source code make files(gyp, gypi).</p>
  
  <p>1) what is the difference between <code>.gyp</code> and <code>.gypi</code> files?</p>
  
  <pre><code>./Source/WebCore/WebCore.gyp/WebCore.gyp
  ./Source/WebCore/WebCore.gyp/gyp/WebCore.gypi
  </code></pre>
  
  <p>2) How can i check which file is compiling for linux/mac/windows chromium code.
  Because when i check the file in <code>.gyp</code> file i show that it list almost all the files of webcore for mac/linux/android/ etc.</p>
  
  <p>above doubt is killing me:(</p>