Browser Plugin: Implement CanGoBack/CanGoForward

content/renderer/browser_plugin/browser_plugin.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/renderer/browser_plugin/browser_plugin.h"
 
 #include "base/message_loop.h"
 #include "base/string_util.h"
 #if defined (OS_WIN)
 #include "base/sys_info.h"
@@ skipping 54 matching lines @@
     : instance_id_(instance_id),
       render_view_(render_view),
       container_(NULL),
       damage_buffer_(NULL),
       sad_guest_(NULL),
       guest_crashed_(false),
       resize_pending_(false),
       navigate_src_sent_(false),
       process_id_(-1),
       persist_storage_(false),
-      visible_(true) {
+      visible_(true),
+      current_nav_entry_index_(0),
+      nav_entry_count_(0) {
   BrowserPluginManager::Get()->AddBrowserPlugin(instance_id, this);
   bindings_.reset(new BrowserPluginBindings(this));
 
   ParseAttributes(params);
 }
 
 BrowserPlugin::~BrowserPlugin() {
   if (damage_buffer_)
     FreeDamageBuffer();
   RemoveEventListeners();
@@ skipping 56 matching lines @@
 
 std::string BrowserPlugin::GetPartitionAttribute() const {
   std::string value;
   if (persist_storage_)
     value.append(kPersistPrefix);
 
   value.append(storage_partition_id_);
   return value;
 }
 
+bool BrowserPlugin::CanGoBack() const {
+  return nav_entry_count_ > 1 && current_nav_entry_index_ > 0;
+}
+
+bool BrowserPlugin::CanGoForward() const {
+  return current_nav_entry_index_ >= 0 &&
+      current_nav_entry_index_ < (nav_entry_count_ - 1);
+}
+
 bool BrowserPlugin::SetPartitionAttribute(const std::string& partition_id,
                                           std::string& error_message) {
   if (navigate_src_sent_) {
     error_message =
       "The object has already navigated, so its partition cannot be changed.";
     return false;
   }
 
   std::string input = partition_id;
 
@@ skipping 168 matching lines @@
     v8::Context::Scope context_scope(v8::Context::New());
     v8::HandleScope handle_scope;
     container()->element().document().frame()->
         callFunctionEvenIfScriptDisabled(*it,
                                          v8::Object::New(),
                                          0,
                                          NULL);
   }
 }
 
+void BrowserPlugin::NavigationStateUpdate(int current_entry_index,
+                                          int entry_count) {
+  current_nav_entry_index_ = current_entry_index;
+  nav_entry_count_ = entry_count;
+}
+
+
 void BrowserPlugin::DidNavigate(const GURL& url, int process_id) {
   src_ = url.spec();
   process_id_ = process_id;
   if (!HasListeners(kNavigationEventName))
     return;
 
   EventListeners& listeners = event_listener_map_[kNavigationEventName];
   EventListeners::iterator it = listeners.begin();
   for (; it != listeners.end(); ++it) {
     v8::Context::Scope context_scope(v8::Context::New());
@@ skipping 390 matching lines @@
                                                  void* notify_data) {
 }
 
 void BrowserPlugin::didFailLoadingFrameRequest(
     const WebKit::WebURL& url,
     void* notify_data,
     const WebKit::WebURLError& error) {
 }
 
 }  // namespace content