Implement evictFrames() to support MSE's coded frame eviction algorithm.

media/filters/source_buffer_stream.cc

Index: media/filters/source_buffer_stream.cc
diff --git a/media/filters/source_buffer_stream.cc b/media/filters/source_buffer_stream.cc
index faba8ec9d1e8d75832cd3ce30296e4c7b766397a..a94d125ccd5fd9cd1c1d0ead99417e9b4315b025 100644
--- a/media/filters/source_buffer_stream.cc
+++ b/media/filters/source_buffer_stream.cc
@@ -348,7 +348,9 @@ bool SourceBufferStream::Append(const BufferQueue& buffers) {
 
   SetSelectedRangeIfNeeded(next_buffer_timestamp);
 
-  GarbageCollectIfNeeded();
+  if (!GarbageCollectIfNeeded()) {
+    LOG(WARNING) << "Buffer capacity exceeded after append";
+  }
 
   DVLOG(1) << __FUNCTION__ << " " << GetStreamTypeName()
            << ": done. ranges_=" << RangesToString(ranges_);
@@ -583,7 +585,7 @@ void SourceBufferStream::SetConfigIds(const BufferQueue& buffers) {
   }
 }
 
-void SourceBufferStream::GarbageCollectIfNeeded() {
+bool SourceBufferStream::GarbageCollectIfNeeded() {
   // Compute size of |ranges_|.
   int ranges_size = 0;
   for (RangeList::iterator itr = ranges_.begin(); itr != ranges_.end(); ++itr)
@@ -591,7 +593,7 @@ void SourceBufferStream::GarbageCollectIfNeeded() {
 
   // Return if we're under or at the memory limit.
   if (ranges_size <= memory_limit_)
-    return;
+    return true;
 
   int bytes_to_free = ranges_size - memory_limit_;
 
@@ -614,6 +616,8 @@ void SourceBufferStream::GarbageCollectIfNeeded() {
   DVLOG(2) << __FUNCTION__ << " " << GetStreamTypeName() << ": After GC"
            << " bytes_freed=" << bytes_freed
            << " ranges_=" << RangesToString(ranges_);
+
+  return (bytes_to_free - bytes_freed <= 0);
 }
 
 int SourceBufferStream::FreeBuffersAfterLastAppended(int total_bytes_to_free) {