Fix some grammatical errors in comments in tools/

tools/traceline/svgui/traceline.js

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // TODO
 //   - spacial partitioning of the data so that we don't have to scan the
 //     entire scene every time we render.
 //   - properly clip the SVG elements when they render, right now we are just
 //     letting them go negative or off the screen.  This might give us a little
 //     bit better performance?
@@ skipping 444 matching lines @@
     // The area we update with the info on mouseovers.
     'infoareadiv': infoareadiv,
     // Called when we detected new scroll a should redraw
     'redraw': function() { },
     'attached': false,
     'attach': function() {
       document.getElementsByTagNameNS(xhtmlNS, 'body')[0].appendChild(
           this.totaldiv);
       this.attached = true;
     },
-    // The fatty div will have it's width adjusted based on the zoom level and
+    // The fatty div will have its width adjusted based on the zoom level and
     // the duration of the graph, to get the scrolling correct for the size.
     'zoom': function(curzoom) {
       var width = widthms * curzoom;
       fattydiv.style.width = width + 'px';
     },
     'detach': function() {
       this.totaldiv.parentNode.removeChild(this.totaldiv);
       this.attached = false;
     },
   };
@@ skipping 208 matching lines @@
     }
 
     ++count;
   }
 
   // Append the 'g' element on after we've build it.
   svg.appendChild(svgg);
 
   return count;
 };