Revert "Make sure to unblock a WebContents during a mass dialog closure."

This reverts commit f7e423bf.

Reason for revert:

This was a speculative fix, thinking that perhaps WillClose() wasn't getting called. But it is, and all the correct calls are being made (see https://bugs.chromium.org/p/chromium/issues/detail?id=880210#c16) so this code only complicates things.

Original change's description:
> Make sure to unblock a WebContents during a mass dialog closure.
> 
> BUG=880210
> 
> Change-Id: I44e80bc0866fef5370936db3f2cb4d3eacf620f2
> Reviewed-on: https://chromium-review.googlesource.com/1241094
> Reviewed-by: Leonard Grey <lgrey@chromium.org>
> Reviewed-by: Mike Wittman <wittman@chromium.org>
> Commit-Queue: Avi Drissman <avi@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#594135}

TBR=avi@chromium.org,wittman@chromium.org,lgrey@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 880210
Change-Id: Ibbd669649add66e0bc4052eb6b04c845ffb40f38
Reviewed-on: https://chromium-review.googlesource.com/1249389Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Leonard Grey <lgrey@chromium.org>
Commit-Queue: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#595166}

components/web_modal/web_contents_modal_dialog_manager.cc

@@ -106,10 +106,6 @@ WebContentsModalDialogManager::DialogState::~DialogState() = default;
 // then set the block state. Advantage: could restrict some of the
 // WCMDM delegate methods, then, and pass them behind the scenes.
 void WebContentsModalDialogManager::BlockWebContentsInteraction(bool blocked) {
-  if (blocked == web_contents_is_blocked_)
-    return;
-  web_contents_is_blocked_ = blocked;
-
   WebContents* contents = web_contents();
   if (!contents) {
     // The WebContents has already disconnected.
@@ -128,7 +124,6 @@ void WebContentsModalDialogManager::CloseAllDialogs() {
   while (!child_dialogs_.empty()) {
     child_dialogs_.front().manager->Close();
   }
-  BlockWebContentsInteraction(false);
 
   closing_all_dialogs_ = false;
 }

components/web_modal/web_contents_modal_dialog_manager.h

@@ -109,9 +109,6 @@ class WebContentsModalDialogManager
   // True while closing the dialogs on WebContents close.
   bool closing_all_dialogs_;
 
-  // True if the WebContents is blocked.
-  bool web_contents_is_blocked_ = false;
-
   DISALLOW_COPY_AND_ASSIGN(WebContentsModalDialogManager);
 };