Update visible ids if any of their thumbnails are invalid

chrome/browser/android/thumbnail/thumbnail_store.cc

 // Copyright 2014 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/thumbnail/thumbnail_store.h"
 
 #include <algorithm>
 #include <cmath>
 
 #include "base/big_endian.h"
@@ skipping 251 matching lines @@
 void ThumbnailStore::UpdateVisibleIds(const TabIdList& priority) {
   if (priority.empty()) {
     visible_ids_.clear();
     return;
   }
 
   size_t ids_size = std::min(priority.size(), cache_.MaximumCacheSize());
   if (visible_ids_.size() == ids_size) {
     // Early out if called with the same input as last time (We only care
     // about the first mCache.MaximumCacheSize() entries).
-    bool lists_differ = false;
+    bool needs_update = false;
     TabIdList::const_iterator visible_iter = visible_ids_.begin();
     TabIdList::const_iterator priority_iter = priority.begin();
     while (visible_iter != visible_ids_.end() &&
            priority_iter != priority.end()) {
-      if (*priority_iter != *visible_iter) {
-        lists_differ = true;
+      if (*priority_iter != *visible_iter || !cache_.Get(*priority_iter)) {
+        needs_update = true;
         break;
       }
       visible_iter++;
       priority_iter++;
     }
 
-    if (!lists_differ)
+    if (!needs_update)
       return;
   }
 
   read_queue_.clear();
   visible_ids_.clear();
   size_t count = 0;
   TabIdList::const_iterator iter = priority.begin();
   while (iter != priority.end() && count < ids_size) {
     TabId tab_id = *iter;
     visible_ids_.push_back(tab_id);
@@ skipping 625 matching lines @@
   dst_bitmap.eraseColor(0);
   SkAutoLockPixels dst_bitmap_lock(dst_bitmap);
 
   SkCanvas canvas(dst_bitmap);
   canvas.scale(new_scale, new_scale);
   canvas.drawBitmap(bitmap, 0, 0, NULL);
   dst_bitmap.setImmutable();
 
   return std::make_pair(dst_bitmap, new_scale * scale);
 }