Bug 846566 - Enable HiDPI for fullscreen plugins by adding an NSPrincipalClass entry to the plugin bundle's Info.plist. r=smichaud

ipc/app/macbuild/Contents/Info.plist.in

@@ -27,7 +27,9 @@
 	</dict>
 	<key>LSUIElement</key>
 	<string>1</string>
-  <key>NSSupportsAutomaticGraphicsSwitching</key>
-  <true/>
+	<key>NSSupportsAutomaticGraphicsSwitching</key>
+	<true/>
+	<key>NSPrincipalClass</key>
+	<string>NSApplication</string>
 </dict>
 </plist>