Fix a crash caused by track insertion after load().

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 0f89c37d54bfecc8a6533843fbee051e2f78930d..5fab19ac1e16f97d9441b65a28131077f6549b9b 100644
--- a/Source/core/html/HTMLMediaElement.cpp
+++ b/Source/core/html/HTMLMediaElement.cpp
@@ -606,6 +606,8 @@ void HTMLMediaElement::prepareForLoad()
     // Perform the cleanup required for the resource load algorithm to run.
     stopPeriodicTimers();
     m_loadTimer.stop();
+    // FIXME: Figure out appropriate place to reset LoadTextTrackResource if necessary and set m_pendingActionFlags to 0 here.

[acolwell GONE FROM CHROMIUM, 2014/03/26 01:13:30]

I will fix this in a follow-up CL since making this 0 now caused many TextTrack
tests to fail and I think fixing in this CL would cloud the main crashing
problem I'm trying to address.

+    m_pendingActionFlags &= ~LoadMediaResource;
     m_sentEndEvent = false;
     m_sentStalledEvent = false;
     m_haveFiredLoadedData = false;