Added function to implement Coded Frame Eviction Algorithm

Source/modules/mediasource/SourceBuffer.cpp

Index: Source/modules/mediasource/SourceBuffer.cpp
diff --git a/Source/modules/mediasource/SourceBuffer.cpp b/Source/modules/mediasource/SourceBuffer.cpp
index e44acdd05d626cece4f1c5cec1854f1354e93d36..066ba8e8d5dc19d8c32cd4d95ad9f42ea7f53616 100644
--- a/Source/modules/mediasource/SourceBuffer.cpp
+++ b/Source/modules/mediasource/SourceBuffer.cpp
@@ -513,7 +513,12 @@ void SourceBuffer::appendBufferInternal(const unsigned char* data, unsigned size
     //  3. If the readyState attribute of the parent media source is in the "ended" state then run the following steps: ...
     m_source->openIfInEndedState();
 
-    //  Steps 4-5 - end "prepare append" algorithm.
+    //  4. Run the coded frame eviction algorithm.
+    if (!evictCodedFrames()) {
+        //  5. If the buffer full flag equals true, then throw a QUOTA_EXCEEDED_ERR exception and abort these steps.

[philipj_slow, 2014/12/10 09:28:26]

I see that we don't have an explicit "buffer full flag" in Chromium or Blink.
That would have made this code more like the spec, but I guess that's OK.

[kjoswiak, 2014/12/10 19:11:45]

Though other thing I considered doing is adding a separate function that just
queried the buffer, asking if its full, instead of relying on this new functions
return value. It felt a little redundant though, so I left it out.

+        exceptionState.throwDOMException(QuotaExceededError, "The SourceBuffer is full, and cannot free space append additional buffers.");

[philipj_slow, 2014/12/10 09:28:26]

missing "to"

[kjoswiak, 2014/12/10 19:11:45]

Done.

+        return;
+    }
 
     // 2. Add data to the end of the input buffer.
     ASSERT(data || size == 0);
@@ -611,6 +616,11 @@ void SourceBuffer::removeAsyncPart()
     scheduleEvent(EventTypeNames::updateend);
 }
 
+bool SourceBuffer::evictCodedFrames()
+{
+    return m_webSourceBuffer->evictCodedFrames();
+}
+
 void SourceBuffer::appendStreamInternal(PassRefPtrWillBeRawPtr<Stream> stream, ExceptionState& exceptionState)
 {
     // Section 3.2 appendStream()
@@ -634,7 +644,13 @@ void SourceBuffer::appendStreamInternal(PassRefPtrWillBeRawPtr<Stream> stream, E
     //  3. If the readyState attribute of the parent media source is in the "ended" state then run the following steps: ...
     m_source->openIfInEndedState();
 
-    // Steps 4-5 of the prepare append algorithm are handled by m_webSourceBuffer.
+    // 4. Run the coded frame eviction algorithm.
+    if (!evictCodedFrames()) {
+        //  5. If the buffer full flag equals true, then throw a QUOTA_EXCEEDED_ERR exception and abort these steps.
+        // TODO(kjoswiak): Is this accurate? Are we actually appending data, or appending a data source?

[philipj_slow, 2014/12/10 09:28:26]

No TODO(user) in Blink, just FIXME. Even better, investigate it and remove the
comment :)

[kjoswiak, 2014/12/10 19:11:45]

whoops meant to remove this, I had actually come to a decision about it,
specifically that since MSE says to run prepare append and this is in the spec
for prepare append its probably best to just leave it in. Done.

+        exceptionState.throwDOMException(QuotaExceededError, "The SourceBuffer is full, and cannot free space to append stream.");
+        return;
+    }
 
     // 2. Set the updating attribute to true.
     m_updating = true;