Add NetLog event for invalid Http/2 response header

net/spdy/chromium/header_coalescer.h

Index: net/spdy/chromium/header_coalescer.h
diff --git a/net/spdy/chromium/header_coalescer.h b/net/spdy/chromium/header_coalescer.h
index 31228adae3468177280b584fb7a14f7fa7d74839..9ba7652acc5b4bf75db1082d680662cd893148c6 100644
--- a/net/spdy/chromium/header_coalescer.h
+++ b/net/spdy/chromium/header_coalescer.h
@@ -6,6 +6,7 @@
 #define NET_SPDY_HEADER_COALESCER_H_
 
 #include "net/base/net_export.h"
+#include "net/log/net_log_with_source.h"
 #include "net/spdy/core/spdy_header_block.h"
 #include "net/spdy/core/spdy_headers_handler_interface.h"
 #include "net/spdy/platform/api/spdy_string_piece.h"
@@ -14,7 +15,7 @@ namespace net {
 
 class NET_EXPORT_PRIVATE HeaderCoalescer : public SpdyHeadersHandlerInterface {
  public:
-  HeaderCoalescer() {}
+  explicit HeaderCoalescer(const NetLogWithSource& net_log);
 
   void OnHeaderBlockStart() override {}
 
@@ -31,11 +32,15 @@ class NET_EXPORT_PRIVATE HeaderCoalescer : public SpdyHeadersHandlerInterface {
   size_t EstimateMemoryUsage() const;
 
  private:
+  // Helper to add a header. Return true on success.
+  bool AddHeader(SpdyStringPiece key, SpdyStringPiece value);
+
   SpdyHeaderBlock headers_;
   bool headers_valid_ = true;
   size_t header_list_size_ = 0;
   bool error_seen_ = false;
   bool regular_header_seen_ = false;
+  NetLogWithSource net_log_;
 };
 
 }  // namespace net