Discard compositor frames from unloaded web content

content/renderer/render_frame_impl.cc

 // Copyright 2013 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/render_frame_impl.h"
 
 #include <map>
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 3581 matching lines @@
     // If this is a provisional frame associated with a proxy (i.e., a frame
     // created for a remote-to-local navigation), swap it into the frame tree
     // now.
     if (!SwapIn())
       return;
   }
 
   // For new page navigations, the browser process needs to be notified of the
   // first paint of that page, so it can cancel the timer that waits for it.
   if (is_main_frame_ && !navigation_state->WasWithinSamePage()) {
+    GetRenderWidget()->IncrementContentSourceId();
     render_view_->QueueMessage(
         new ViewHostMsg_DidFirstPaintAfterLoad(render_view_->routing_id_),
         MESSAGE_DELIVERY_POLICY_WITH_VISUAL_STATE);
   }
 
   // When we perform a new navigation, we need to update the last committed
   // session history entry with state for the page we are leaving. Do this
   // before updating the current history item.
   SendUpdateState();
 
@@ skipping 1252 matching lines @@
 
   params.gesture = render_view_->navigation_gesture_;
   render_view_->navigation_gesture_ = NavigationGestureUnknown;
 
   // Make navigation state a part of the DidCommitProvisionalLoad message so
   // that committed entry has it at all times.  Send a single HistoryItem for
   // this frame, rather than the whole tree.  It will be stored in the
   // corresponding FrameNavigationEntry.
   params.page_state = SingleHistoryItemToPageState(item);
 
+  params.content_source_id = GetRenderWidget()->GetContentSourceId();
+
   params.method = request.httpMethod().latin1();
   if (params.method == "POST")
     params.post_id = ExtractPostId(item);
 
   params.frame_unique_name = item.target().utf8();
   params.item_sequence_number = item.itemSequenceNumber();
   params.document_sequence_number = item.documentSequenceNumber();
 
   // If the page contained a client redirect (meta refresh, document.loc...),
   // set the referrer appropriately.
@@ skipping 1959 matching lines @@
   // event target. Potentially a Pepper plugin will receive the event.
   // In order to tell whether a plugin gets the last mouse event and which it
   // is, we set |pepper_last_mouse_event_target_| to null here. If a plugin gets
   // the event, it will notify us via DidReceiveMouseEvent() and set itself as
   // |pepper_last_mouse_event_target_|.
   pepper_last_mouse_event_target_ = nullptr;
 #endif
 }
 
 }  // namespace content