Limit the total memory usage for Stream instances

content/browser/streams/stream_registry.h

Index: content/browser/streams/stream_registry.h
diff --git a/content/browser/streams/stream_registry.h b/content/browser/streams/stream_registry.h
index e75c97c1699ae1f625180b929bdc779c2696a619..a359411d2ae4f3c6b35fa2c732bc0c59e17e84c2 100644
--- a/content/browser/streams/stream_registry.h
+++ b/content/browser/streams/stream_registry.h
@@ -32,20 +32,37 @@ class CONTENT_EXPORT StreamRegistry : public base::NonThreadSafe {
 
   void UnregisterStream(const GURL& url);
 
+  // Called by Stream instances to request increase of memory usage. If the
+  // total memory usage for this registry is going to exceed the limit,
+  // returns false. Otherwise, updates |total_memory_usage_| and returns true.
+  //
+  // |current_size| is the up-to-date size of ByteStream of the Stream instance
+  // and |increase| must be the amount of data going to be added to the Stream
+  // instance.
+  bool UpdateMemoryUsage(const GURL& url, size_t current_size, size_t increase);
+
   // Gets the stream associated with |url|.  Returns NULL if there is no such
   // stream.
   scoped_refptr<Stream> GetStream(const GURL& url);
 
+  void set_max_memory_usage_for_testing(size_t size) {
+    max_memory_usage_ = size;
+  }
+
  private:
   typedef std::map<GURL, scoped_refptr<Stream> > StreamMap;
 
   StreamMap streams_;
 
+  size_t total_memory_usage_;
+
+  // Maximum amount of memory allowed to use for Stream instances registered
+  // with this registry.
+  size_t max_memory_usage_;
+
   DISALLOW_COPY_AND_ASSIGN(StreamRegistry);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_STREAMS_STREAM_REGISTRY_H_
-
-