This patch:
- Passes in a reference to the current PDFThumbnailViewer, which is used to ensure that the current thumbnail becomes visible when exiting PresentationMode.
- Changes the way that the event listeners for the contextmenu items are defined, to avoid passing in a reference to the SecondaryToolbar.
- Ensures that |supportsFullscreen| always returns a boolean.
Currently `supportsFullscreen` will, when the browser supports the fullscreen API, return e.g. `function mozRequestFullScreen()` instead of `true`.
- Simplifies the |click| handler code when PresentationMode is active.
This code has been obsolete ever since PR 2919 landed.
- Removes hack used to workaround a bug in WebKit browsers, which caused |mousemove| events to be fired when the cursor changed.
This was fixed close to a year ago, see http://code.google.com/p/chromium/issues/detail?id=103041.