Cap the memory usage in FFMpegDemuxer.

media/base/decoder_buffer_queue.cc

Index: media/base/decoder_buffer_queue.cc
diff --git a/media/base/decoder_buffer_queue.cc b/media/base/decoder_buffer_queue.cc
index d0486cbf93965932bcbf7108f24cd947f79c499c..365735ff03a3041356564c2b50883d90d1f6219f 100644
--- a/media/base/decoder_buffer_queue.cc
+++ b/media/base/decoder_buffer_queue.cc
@@ -4,6 +4,8 @@
 
 #include "media/base/decoder_buffer_queue.h"
 
+#include <limits>
+
 #include "base/logging.h"
 #include "media/base/buffers.h"
 #include "media/base/decoder_buffer.h"
@@ -11,7 +13,8 @@
 namespace media {
 
 DecoderBufferQueue::DecoderBufferQueue()
-    : earliest_valid_timestamp_(kNoTimestamp()) {
+    : earliest_valid_timestamp_(kNoTimestamp()),
+      data_size_(0) {
 }
 
 DecoderBufferQueue::~DecoderBufferQueue() {}
@@ -21,6 +24,9 @@ void DecoderBufferQueue::Push(const scoped_refptr<DecoderBuffer>& buffer) {
 
   queue_.push_back(buffer);
 
+  DCHECK_LE(buffer->data_size(), std::numeric_limits<int>::max() - data_size_);
+  data_size_ += buffer->data_size();
+
   // TODO(scherkus): FFmpeg returns some packets with no timestamp after
   // seeking. Fix and turn this into CHECK(). See http://crbug.com/162192
   if (buffer->timestamp() == kNoTimestamp()) {
@@ -49,6 +55,9 @@ scoped_refptr<DecoderBuffer> DecoderBufferQueue::Pop() {
   scoped_refptr<DecoderBuffer> buffer = queue_.front();
   queue_.pop_front();
 
+  data_size_ -= buffer->data_size();
+  DCHECK_GE(data_size_, 0);
+
   if (!in_order_queue_.empty() &&
       in_order_queue_.front().get() == buffer.get()) {
     in_order_queue_.pop_front();
@@ -59,6 +68,7 @@ scoped_refptr<DecoderBuffer> DecoderBufferQueue::Pop() {
 
 void DecoderBufferQueue::Clear() {
   queue_.clear();
+  data_size_ = 0;
   in_order_queue_.clear();
   earliest_valid_timestamp_ = kNoTimestamp();
 }