Changed the semantics of Buffer::Clear to not alter the capacity

webrtc/base/buffer.h

Index: webrtc/base/buffer.h
diff --git a/webrtc/base/buffer.h b/webrtc/base/buffer.h
index 5c9380afee03a5e0825d92475e9ed578244314ae..234039607a1c862aa11763936ec236380d3252c5 100644
--- a/webrtc/base/buffer.h
+++ b/webrtc/base/buffer.h
@@ -180,12 +180,10 @@ class Buffer {
     return std::move(*this);
   }
 
-  // Resets the buffer to zero size and capacity. Works even if the buffer has
-  // been moved from.
+  // Resets the buffer to zero size without altering capacity. Works even if the
+  // buffer has been moved from.
   void Clear() {
-    data_.reset();
     size_ = 0;
-    capacity_ = 0;
     assert(IsConsistent());
   }