Fix race condition for non-started fast tracks

This required re-implementing how fast tracks are considered active.
Now, they use the same logic as normal tracks, except underrun is ignored.

Other changes:
 - add framesReady() to AudioBufferProvider interface
 - rebased
 - add track underrun counter state to fast mixer dump state
 - move dumpsys header to Track::appendDumpHeader()
   so it closer to where tracks are dumped
 - display track state in dumpsys as a character code
 - measure and display warmup time and cycles in dumpsys
 - copy in the presentation complete code
 - add ExtendedAudioBufferProvider for framesReady() which returns size_t
 - simplify underrun tracking
 - deferred reset track after stop()
 - add comments

Change-Id: I7db8821bc565230ec76da1f9380fe3fb09735e5b
diff --git a/services/audioflinger/ExtendedAudioBufferProvider.h b/services/audioflinger/ExtendedAudioBufferProvider.h
new file mode 100644
index 0000000..88279b4
--- /dev/null
+++ b/services/audioflinger/ExtendedAudioBufferProvider.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_EXTENDED_AUDIO_BUFFER_PROVIDER_H
+#define ANDROID_EXTENDED_AUDIO_BUFFER_PROVIDER_H
+
+#include "AudioBufferProvider.h"
+
+namespace android {
+
+class ExtendedAudioBufferProvider : public AudioBufferProvider {
+public:
+    virtual size_t  framesReady() const = 0;  // see description at AudioFlinger.h
+};
+
+}   // namespace android
+
+#endif  // ANDROID_EXTENDED_AUDIO_BUFFER_PROVIDER_H