Prevent bindings escalation on an existing NavigationEntry (attempt 3).

content/browser/web_contents/navigation_entry_impl.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 "content/browser/web_contents/navigation_entry_impl.h"
 
 #include "base/metrics/histogram.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "content/public/common/content_constants.h"
 #include "content/public/common/url_constants.h"
 #include "net/base/net_util.h"
 #include "ui/base/text/text_elider.h"
 
 // Use this to get a new unique ID for a NavigationEntry during construction.
 // The returned ID is guaranteed to be nonzero (which is the "no ID" indicator).
 static int GetUniqueIDInConstructor() {
   static int unique_id_counter = 0;
   return ++unique_id_counter;
 }
 
 namespace content {
 
+int NavigationEntryImpl::kInvalidBindings = -1;
+
 NavigationEntry* NavigationEntry::Create() {
   return new NavigationEntryImpl();
 }
 
 NavigationEntry* NavigationEntry::Create(const NavigationEntry& copy) {
   return new NavigationEntryImpl(static_cast<const NavigationEntryImpl&>(copy));
 }
 
 NavigationEntryImpl* NavigationEntryImpl::FromNavigationEntry(
     NavigationEntry* entry) {
   return static_cast<NavigationEntryImpl*>(entry);
 }
 
 NavigationEntryImpl::NavigationEntryImpl()
     : unique_id_(GetUniqueIDInConstructor()),
       site_instance_(NULL),
+      bindings_(kInvalidBindings),
       page_type_(PAGE_TYPE_NORMAL),
       update_virtual_url_with_url_(false),
       page_id_(-1),
       transition_type_(PAGE_TRANSITION_LINK),
       has_post_data_(false),
       post_id_(-1),
       restore_type_(RESTORE_NONE),
       is_overriding_user_agent_(false),
       is_renderer_initiated_(false),
       should_replace_entry_(false),
       can_load_local_resources_(false) {
 }
 
 NavigationEntryImpl::NavigationEntryImpl(SiteInstanceImpl* instance,
                                          int page_id,
                                          const GURL& url,
                                          const Referrer& referrer,
                                          const string16& title,
                                          PageTransition transition_type,
                                          bool is_renderer_initiated)
     : unique_id_(GetUniqueIDInConstructor()),
       site_instance_(instance),
+      bindings_(kInvalidBindings),
       page_type_(PAGE_TYPE_NORMAL),
       url_(url),
       referrer_(referrer),
       update_virtual_url_with_url_(false),
       title_(title),
       page_id_(page_id),
       transition_type_(transition_type),
       has_post_data_(false),
       post_id_(-1),
       restore_type_(RESTORE_NONE),
@@ skipping 70 matching lines @@
 }
 
 int32 NavigationEntryImpl::GetPageID() const {
   return page_id_;
 }
 
 void NavigationEntryImpl::set_site_instance(SiteInstanceImpl* site_instance) {
   site_instance_ = site_instance;
 }
 
+void NavigationEntryImpl::SetBindings(int bindings) {
+  // Ensure this is set to a valid value, and that it stays the same once set.
+  CHECK_NE(bindings, kInvalidBindings);
+  CHECK(bindings_ == kInvalidBindings || bindings_ == bindings);
+  bindings_ = bindings;
+}
+
 const string16& NavigationEntryImpl::GetTitleForDisplay(
     const std::string& languages) const {
   // Most pages have real titles. Don't even bother caching anything if this is
   // the case.
   if (!title_.empty())
     return title_;
 
   // More complicated cases will use the URLs as the title. This result we will
   // cache since it's more complicated to compute.
   if (!cached_display_title_.empty())
@@ skipping 137 matching lines @@
 }
 
 void NavigationEntryImpl::SetScreenshotPNGData(
     const std::vector<unsigned char>& png_data) {
   screenshot_ = png_data.empty() ? NULL : new base::RefCountedBytes(png_data);
   if (screenshot_)
     UMA_HISTOGRAM_MEMORY_KB("Overscroll.ScreenshotSize", screenshot_->size());
 }
 
 }  // namespace content