Add rule to platform apps default CSS to allow user selection within content-editable elements.

BUG=226459


Review URL: https://chromiumcodereview.appspot.com/13801013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@193528 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/renderer/resources/extensions/platform_app.css b/chrome/renderer/resources/extensions/platform_app.css
index 03bab4d..a51d4f6 100644
--- a/chrome/renderer/resources/extensions/platform_app.css
+++ b/chrome/renderer/resources/extensions/platform_app.css
@@ -26,3 +26,8 @@
 img, a {
   -webkit-user-drag: none;
 }
+
+[contenteditable], input {
+  -webkit-user-select: auto;
+}
+