[not for review] Add Draw entries to window Performance Timeline

Source/core/frame/Frame.cpp

Index: Source/core/frame/Frame.cpp
diff --git a/Source/core/frame/Frame.cpp b/Source/core/frame/Frame.cpp
index f647b3e5988b5ed202236a17a12183a39112612d..ee59886127e7e75d5d92604494dd6981f356b64f 100644
--- a/Source/core/frame/Frame.cpp
+++ b/Source/core/frame/Frame.cpp
@@ -55,6 +55,18 @@ 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);
+    return ++next;
+}
+
+} // namespace
+
 DEFINE_DEBUG_ONLY_GLOBAL(WTF::RefCountedLeakCounter, frameCounter, ("Frame"));
 
 Frame::Frame(FrameClient* client, FrameHost* host, FrameOwner* owner)
@@ -62,6 +74,7 @@ Frame::Frame(FrameClient* client, FrameHost* host, FrameOwner* owner)
     , m_host(host)
     , m_owner(owner)
     , m_client(client)
+    , m_frameID(generateFrameID())
     , m_remotePlatformLayer(0)
 {
     ASSERT(page());