Improve memory estimate of SpdySessionPool in net/ MemoryDumpProvider.

net/spdy/http2_frame_decoder_adapter.cc

Index: net/spdy/http2_frame_decoder_adapter.cc
diff --git a/net/spdy/http2_frame_decoder_adapter.cc b/net/spdy/http2_frame_decoder_adapter.cc
index 475ef17d45b3bb8fd324bf2a38f46f2d27ef20f1..64d6b6d5d43fb50201cbb710d0e38c42165a1812 100644
--- a/net/spdy/http2_frame_decoder_adapter.cc
+++ b/net/spdy/http2_frame_decoder_adapter.cc
@@ -28,6 +28,7 @@
 #include "net/http2/http2_structures.h"
 #include "net/spdy/hpack/hpack_decoder_interface.h"
 #include "net/spdy/hpack/hpack_header_table.h"
+#include "net/spdy/platform/api/spdy_estimate_memory_usage.h"
 #include "net/spdy/spdy_alt_svc_wire_format.h"
 #include "net/spdy/spdy_bug_tracker.h"
 #include "net/spdy/spdy_frame_builder.h"
@@ -143,6 +144,12 @@ class Http2DecoderAdapter : public SpdyFramerDecoderAdapter,
     return latched_probable_http_response_;
   }
 
+  size_t EstimateMemoryUsage() const override {
+    // Skip |frame_decoder_|, |frame_header_| and |hpack_first_frame_header_| as
+    // they don't allocate.
+    return SpdyEstimateMemoryUsage(alt_svc_origin_) +
+           SpdyEstimateMemoryUsage(alt_svc_value_);
+  }
   // ===========================================================================
   // Implementations of the methods declared by Http2FrameDecoderListener.