Add a inner text parameter to ContextMenuParams

ios/web/web_state/ui/crw_web_controller.mm

Index: ios/web/web_state/ui/crw_web_controller.mm
diff --git a/ios/web/web_state/ui/crw_web_controller.mm b/ios/web/web_state/ui/crw_web_controller.mm
index ae654fe4b9d2caab44fab59d6530da861a25a67a..fbb9b7917dc28adccfec613e4005b26d107ab9d8 100644
--- a/ios/web/web_state/ui/crw_web_controller.mm
+++ b/ios/web/web_state/ui/crw_web_controller.mm
@@ -4290,6 +4290,10 @@ const NSTimeInterval kSnapshotOverlayTransition = 0.5;
     params.referrer_policy =
         web::ReferrerPolicyFromString(base::SysNSStringToUTF8(referrerPolicy));
   }
+  NSString* innerText = element[@"innerText"];

[marq (ping after 24h), 2016/10/03 11:31:09]

If the JS innerText value is an empty string, what is the behavior here? Is
|innerText| null or an empty NSString? And what is the expected behavior of code
that uses the params struct?

(Ideally document in the params struct header whether the string can be empty or
not). 

[gambard, 2016/10/03 12:05:52]

The string can be empty or potentially nil (if the HTML element is not a <a/>).
Done.

+  if (innerText) {
+    params.inner_text.reset([innerText copy]);
+  }
   return params;
 }