When unblocking a WebContents, don't bring it to the front if it is not already.

chrome/browser/ui/browser.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/browser.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <string>
@@ skipping 1882 matching lines @@
 // Browser, web_modal::WebContentsModalDialogManagerDelegate implementation:
 
 void Browser::SetWebContentsBlocked(content::WebContents* web_contents,
                                     bool blocked) {
   int index = tab_strip_model_->GetIndexOfWebContents(web_contents);
   if (index == TabStripModel::kNoTab) {
     NOTREACHED();
     return;
   }
   tab_strip_model_->SetTabBlocked(index, blocked);
-  if (!blocked && tab_strip_model_->GetActiveWebContents() == web_contents)
+
+  bool browser_active = BrowserList::GetInstance()->GetLastActive() == this;
+  bool contents_is_active =
+      tab_strip_model_->GetActiveWebContents() == web_contents;
+  // If the WebContents is foremost (the active tab in the front-most browser)
+  // and is being unblocked, focus it to make sure that input works again.
+  if (!blocked && contents_is_active && browser_active)

[Lei Zhang, 2016/10/24 22:43:15]

Maybe return early if |blocked| is true?

[Avi (use Gerrit), 2016/10/25 15:07:08]

There are three conditions to focusing it; it feels weird to me to test just
one, unless you're worried about the cost of calculating the others, but how
often does this happen?

[Lei Zhang, 2016/10/25 17:31:43]

I'm not that worried about it. I just saw it from the "it already failed, why
keep going" perspective.

     web_contents->Focus();
 }
 
 web_modal::WebContentsModalDialogHost*
 Browser::GetWebContentsModalDialogHost() {
   return window_->GetWebContentsModalDialogHost();
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 // Browser, BookmarkTabHelperDelegate implementation:
@@ skipping 663 matching lines @@
   if (contents && !allow_js_access) {
     contents->web_contents()->GetController().LoadURL(
         target_url,
         content::Referrer(),
         ui::PAGE_TRANSITION_LINK,
         std::string());  // No extra headers.
   }
 
   return contents != NULL;
 }