Do NULL checks on TabAndroids retrieved from the model

chrome/browser/android/dev_tools_server.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/android/dev_tools_server.h"
 
 #include <pwd.h>
 #include <cstring>
 
 #include "base/android/jni_string.h"
@@ skipping 170 matching lines @@
 
   virtual scoped_refptr<DevToolsAgentHost> GetAgentHost() const OVERRIDE {
     TabModel* model;
     int index;
     if (!FindTab(&model, &index))
       return NULL;
     WebContents* web_contents = model->GetWebContentsAt(index);
     if (!web_contents) {
       // The tab has been pushed out of memory, pull it back.
       TabAndroid* tab = model->GetTabAt(index);
+      if (!tab)
+        return NULL;
+
       tab->LoadIfNeeded();
       web_contents = model->GetWebContentsAt(index);
       if (!web_contents)
         return NULL;
     }
     return DevToolsAgentHost::GetOrCreateFor(web_contents);
   }
 
   virtual bool Activate() const OVERRIDE {
     TabModel* model;
@@ skipping 23 matching lines @@
       : TargetBase(base::UTF16ToUTF8(title), url),
         tab_id_(tab_id) {
   }
 
   bool FindTab(TabModel** model_result, int* index_result) const {
     for (TabModelList::const_iterator iter = TabModelList::begin();
         iter != TabModelList::end(); ++iter) {
       TabModel* model = *iter;
       for (int i = 0; i < model->GetTabCount(); ++i) {
         TabAndroid* tab = model->GetTabAt(i);
-        if (tab->GetAndroidId() == tab_id_) {
+        if (tab && tab->GetAndroidId() == tab_id_) {
           *model_result = model;
           *index_result = i;
           return true;
         }
       }
     }
     return false;
   }
 
   const int tab_id_;
@@ skipping 111 matching lines @@
   virtual void EnumerateTargets(TargetCallback callback) OVERRIDE {
     TargetList targets;
 
     // Enumerate existing tabs, including the ones with no WebContents.
     std::set<WebContents*> tab_web_contents;
     for (TabModelList::const_iterator iter = TabModelList::begin();
         iter != TabModelList::end(); ++iter) {
       TabModel* model = *iter;
       for (int i = 0; i < model->GetTabCount(); ++i) {
         TabAndroid* tab = model->GetTabAt(i);
+        if (!tab)
+          continue;
+
         WebContents* web_contents = model->GetWebContentsAt(i);
         if (web_contents) {
           tab_web_contents.insert(web_contents);
           targets.push_back(TabTarget::CreateForWebContents(tab->GetAndroidId(),
                                                             web_contents));
         } else {
           targets.push_back(TabTarget::CreateForUnloadedTab(tab->GetAndroidId(),
                                                             tab->GetTitle(),
                                                             tab->GetURL()));
         }
@@ skipping 162 matching lines @@
                                       jlong server,
                                       jboolean enabled,
                                       jboolean allow_debug_permission) {
   DevToolsServer* devtools_server = reinterpret_cast<DevToolsServer*>(server);
   if (enabled) {
     devtools_server->Start(allow_debug_permission);
   } else {
     devtools_server->Stop();
   }
 }