Remove AppNap support from Chrome browser process.

This is a speculative fix for Chrome being unusable after unlocking the machine
after several hours/days of not being used. Our current best theory is that the
browser process goes to sleep but the renderer keeps running [and sending IPCs].
When the browser wakes up, it must spend all its time processing those IPCs,
many of which involve writing to disk.

Bug: 808031
Change-Id: Iff94f6a14cb3f3037ba43da19f32cec915b9fdb3
Reviewed-on: https://chromium-review.googlesource.com/1057458Reviewed-by: Leonard Grey <lgrey@chromium.org>
Commit-Queue: Erik Chen <erikchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558310}

chrome/app/app-Info.plist

@@ -350,7 +350,5 @@
 	</array>
         <key>NSUserNotificationAlertStyle</key>
         <string>banner</string>
-	<key>NSSupportsAppNap</key>
-	<true/>
 </dict>
 </plist>