Resolve the issue of unexpected currentTime values when setting currentTime from seeking event

Source/core/html/HTMLMediaElement.cpp

Index: Source/core/html/HTMLMediaElement.cpp
diff --git a/Source/core/html/HTMLMediaElement.cpp b/Source/core/html/HTMLMediaElement.cpp
index 4da8ea7bc447051a7ee714c4d5aff3c817e1cfc7..381668f1b47a2bcc5c65deb24e3fb44822ca41ca 100644
--- a/Source/core/html/HTMLMediaElement.cpp
+++ b/Source/core/html/HTMLMediaElement.cpp
@@ -1718,7 +1718,11 @@ void HTMLMediaElement::seek(double time, ExceptionState& exceptionState)
 
     // 3 - Set the seeking IDL attribute to true.
     // The flag will be cleared when the engine tells us the time has actually changed.
-    m_seeking = true;
+    bool seekPending = false;

[acolwell GONE FROM CHROMIUM, 2014/04/16 15:33:13]

nit: Just assign m_seeking to seekPending here and drop the conditional below.
Also a name like previousSeekStillPending might eliminate the need for the
comment where this variable is used below.

+    if (m_seeking)
+        seekPending = true;
+    else
+        m_seeking = true;
 
     // 5 - If the new playback position is later than the end of the media resource, then let it be the end
     // of the media resource instead.
@@ -1758,6 +1762,10 @@ void HTMLMediaElement::seek(double time, ExceptionState& exceptionState)
     if (noSeekRequired) {
         if (time == now) {
             scheduleEvent(EventTypeNames::seeking);
+            // An old seek event is still in progress for the same time value, so return from here
+            // and let media engine process it and update the status
+            if (seekPending)
+                return;
             // FIXME: There must be a stable state before timeupdate+seeked are dispatched and seeking
             // is reset to false. See http://crbug.com/266631
             scheduleTimeupdateEvent(false);