Fixed the speech crash when the render view has gone away then users click "try again"

chrome/browser/speech/chrome_speech_recognition_manager_delegate.cc

 // Copyright (c) 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/speech/chrome_speech_recognition_manager_delegate.h"
 
 #include <set>
 #include <string>
 
 #include "base/bind.h"
@@ skipping 257 matching lines @@
 
   // Note, the session might have been destroyed, therefore avoid calls to the
   // manager which imply its existance (e.g., GetSessionContext()).
   GetBubbleController()->CloseBubble();
   last_session_config_.reset();
 
   // Clicking outside the bubble means we should abort.
   SpeechRecognitionManager::GetInstance()->AbortSession(session_id);
 }
 
 void ChromeSpeechRecognitionManagerDelegate::RestartLastSession() {

[tommi (sloooow) - chröme, 2013/03/28 10:38:46]

Hmm... rename to MaybeRestartLastSession?

-  DCHECK(last_session_config_.get());
+  if (!last_session_config_.get())
+    return;

[tommi (sloooow) - chröme, 2013/03/28 10:38:46]

what effect does this have on the functionality?
Also, please add a comment for how we can get here.

+
   SpeechRecognitionManager* manager = SpeechRecognitionManager::GetInstance();
   const int new_session_id = manager->CreateSession(*last_session_config_);
   DCHECK_NE(SpeechRecognitionManager::kSessionIDInvalid, new_session_id);
   last_session_config_.reset();
   manager->StartSession(new_session_id);
 }
 
 void ChromeSpeechRecognitionManagerDelegate::TabClosedCallback(
     int render_process_id, int render_view_id) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
@@ skipping 14 matching lines @@
   }
 }
 
 void ChromeSpeechRecognitionManagerDelegate::OnRecognitionStart(
     int session_id) {
   const content::SpeechRecognitionSessionContext& context =
       SpeechRecognitionManager::GetInstance()->GetSessionContext(session_id);
 
   if (RequiresBubble(session_id)) {
     // Copy the configuration of the session (for the "try again" button).
     last_session_config_.reset(new content::SpeechRecognitionSessionConfig(

[tommi (sloooow) - chröme, 2013/03/28 10:38:46]

I'm looking for this constructor in the code but I can't find it! :)
I only see a default constructor for this type:
https://code.google.com/p/chromium/codesearch#chromium/src/content/public/bro...

Was it added very recently or has it been removed?

         SpeechRecognitionManager::GetInstance()->GetSessionConfig(session_id)));
 
     // Create and show the bubble.
     GetBubbleController()->CreateBubble(session_id,
                                         context.render_process_id,
                                         context.render_view_id,
                                         context.element_rect);
   }
 
   // Register callback to auto abort session on tab closure.
@@ skipping 140 matching lines @@
                                      context.render_process_id,
                                      context.render_view_id,
                                      RequiresTrayIcon(session_id)));
 }
 
 content::SpeechRecognitionEventListener*
 ChromeSpeechRecognitionManagerDelegate::GetEventListener() {
   return this;
 }
 
+void ChromeSpeechRecognitionManagerDelegate::OnAbortSessionsForListener(
+    SpeechRecognitionEventListener* listener) {

[tommi (sloooow) - chröme, 2013/03/28 10:38:46]

Passing the listener here feels hacky.  I would rather want to have something
like:
OnSessionAborted(int session_id)

Or if there's at most ever only one session active, then no parameter.
In what cases can this function be called and the listener does not match
last_session_config_->event_listener?

+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  if (last_session_config_->event_listener == listener)
+    last_session_config_.reset();
+}
+
 void ChromeSpeechRecognitionManagerDelegate::CheckRenderViewType(
     base::Callback<void(bool ask_user, bool is_allowed)> callback,
     int render_process_id,
     int render_view_id,
     bool js_api) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   const content::RenderViewHost* render_view_host =
       content::RenderViewHost::FromID(render_process_id, render_view_id);
 
   bool allowed = false;
@@ skipping 38 matching lines @@
 }
 
 SpeechRecognitionBubbleController*
 ChromeSpeechRecognitionManagerDelegate::GetBubbleController() {
   if (!bubble_controller_.get())
     bubble_controller_ = new SpeechRecognitionBubbleController(this);
   return bubble_controller_.get();
 }
 
 }  // namespace speech