[ios] Remove the openJavascript method from Tab.

ios/chrome/browser/ui/browser_view_controller.mm

Index: ios/chrome/browser/ui/browser_view_controller.mm
diff --git a/ios/chrome/browser/ui/browser_view_controller.mm b/ios/chrome/browser/ui/browser_view_controller.mm
index af75824e2ee01794856eb8717e2f8076bebf0294..6734972d92d8f334056ae2f17be19cd65972548b 100644
--- a/ios/chrome/browser/ui/browser_view_controller.mm
+++ b/ios/chrome/browser/ui/browser_view_controller.mm
@@ -3787,7 +3787,12 @@ class BrowserBookmarkModelBridge : public bookmarks::BookmarkModelObserver {
 }
 
 - (void)openJavascript:(NSString*)javascript {
-  [[_model currentTab] openJavascript:javascript];
+  DCHECK(javascript);
+  javascript = [javascript stringByRemovingPercentEncoding];

[rohitrao (ping after 24h), 2017/01/19 21:59:09]

Is this sanitization important?

[Eugene But (OOO till 7-30), 2017/01/19 22:20:33]

I don't know.

+  web::WebState* web_state = [[_model currentTab] webState];

[Eugene But (OOO till 7-30), 2017/01/19 22:20:34]

s/web_state/webState

[rohitrao (ping after 24h), 2017/01/20 16:12:17]

Done.

+  if (web_state) {
+    web_state->ExecuteJavaScript(base::SysNSStringToUTF16(javascript));

[rohitrao (ping after 24h), 2017/01/19 21:59:09]

This is a little dumb because we go from UTF8 -> NSString -> UTF16 -> NSString
=)  I can probably remove one of those conversions.

[Eugene But (OOO till 7-30), 2017/01/19 22:20:33]

This is user supplied JS. I don't think they can type so much code to cause a
performance problem :)

[rohitrao (ping after 24h), 2017/01/20 16:12:17]

This is not actually true.  The JS supplied here comes from links in the page,
so they can probably be arbitrarily large.

[Eugene But (OOO till 7-30), 2017/01/20 18:05:18]

So maybe we should change WebState::ExecuteJavaScript to take NSString? I
created this method with sting16 signature to match content API, but in this
case it looks like diverging is reasonable.

+  }
 }
 
 #pragma mark - WebToolbarDelegate methods