Added side slide gestures to touch exploration controller.
The user can control settings that might be normally changed using sliders by sliding along the edge of the screen when ChromeVox is on. For example, the user can slide along the right edge of the screen and adjust the volume.
If the user enters this mode and leaves the boundaries without releasing their touch, they will stop adjusting the setting, however, they will not enter touch exploration. If they return to the given boundaries, they will be able to modify the setting again. If the user does not touch a "hot edge" of the screen, they will not enter this state if they move to the an of the screen.
BUG=393326
Review URL: https://codereview.chromium.org/385073009
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@284819 0039d316-1c4b-4281-b951-d872f2087c98
12 files changed
