title: getUserMedia not capturing the screen correctly
body: <p>Using the following code:</p>
  
  <pre><code>function captureScreen(size) {
      navigator.webkitGetUserMedia({
          audio: false,
          video: {
              mandatory: {
                  chromeMediaSource: 'desktop',
                  minWidth: size.width,
                  maxWidth: size.width,
                  minHeight: size.height,
                  maxHeight: size.height,
                  minFrameRate: 1,
                  maxFrameRate: 1
              }
          }
      }, gotStream, getUserMediaError);
  
      function gotStream(stream) {
          var video = document.createElement('video');
          video.addEventListener('loadedmetadata',function(){
              var canvas = document.createElement('canvas');
              canvas.width = this.videoWidth;
              canvas.height = this.videoHeight;
              var context = canvas.getContext("2d");
              context.drawImage(this, 0, 0);
          },false);
          video.src = URL.createObjectURL(stream);
      }
  
      function getUserMediaError(e) {
          console.log('getUserMediaError: ' + JSON.stringify(e, null, '---'));
      }
  }
  </code></pre>
  
  <p>Gives me the following result:</p>
  
  <p><a href="https://i.stack.imgur.com/B6IO4.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/B6IO4.jpg" alt="enter image description here"></a></p>
  
  <p>Notice how the right side of the image is slightly wrapped to the left side? For some reason, this happens on my laptop (1366x768), a friend's laptop (1366x768), but not my desktop (3840x1080 dual screen). the <code>size</code> parameter passed to the function is always the correct and actual size of the entire desktop area. Even when I hardcode the min and max width / height, I get the same result. Is there any way to fix this? Am I doing something wrong?</p>
  
  <p>I'm building an Electron app which needs to take a screenshot of the user's desktop. There's also nothing else on the web page, and I am using a reset CSS.</p>