Blink changes to record interest rects for http://w3c.github.io/frame-timing/

Source/core/frame/Frame.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Simon Hausmann <hausmann@kde.org>
  *                     2000 Stefan Schimanski <1Stein@gmx.de>
  *                     2001 George Staikos <staikos@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2005 Alexey Proskuryakov <ap@nypop.com>
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
@@ skipping 35 matching lines @@
 #include "core/page/EventHandler.h"
 #include "core/page/FocusController.h"
 #include "core/page/Page.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/RefCountedLeakCounter.h"
 
 namespace blink {
 
 using namespace HTMLNames;
 
+namespace {
+
+int64_t generateFrameID()
+{
+    // Initialize to the current time to reduce the likelihood of generating
+    // identifiers that overlap with those from past/future browser sessions.
+    static int64_t next = static_cast<int64_t>(currentTime() * 1000000.0);

[chrishtr, 2015/03/27 01:13:02]

currentTime() is already in seconds, no?

[MikeB, 2015/04/14 18:05:45]

Yes, it's making "next" start off at a very large number, seeded by the time. It
will increment by "1" though, for each frame. If it used "seconds" then there's
a very real chance of collisions. 

+    return ++next;
+}
+
+} // namespace
+
 DEFINE_DEBUG_ONLY_GLOBAL(WTF::RefCountedLeakCounter, frameCounter, ("Frame"));
 
 Frame::~Frame()
 {
     ASSERT(!m_owner);
 #ifndef NDEBUG
     frameCounter.decrement();
 #endif
 }
 
@@ skipping 213 matching lines @@
     if (m_host)
         return &m_host->settings();
     return nullptr;
 }
 
 Frame::Frame(FrameClient* client, FrameHost* host, FrameOwner* owner)
     : m_treeNode(this)
     , m_host(host)
     , m_owner(owner)
     , m_client(client)
+    , m_frameID(generateFrameID())
     , m_isLoading(false)
 {
     ASSERT(page());
 
 #ifndef NDEBUG
     frameCounter.increment();
 #endif
 
     if (m_owner) {
         if (m_owner->isLocal())
             toHTMLFrameOwnerElement(m_owner)->setContentFrame(*this);
     } else {
         page()->setMainFrame(this);
     }
 }
 
 } // namespace blink