Add HttpCache histograms focussed on blocking and transaction type.

net/http/http_cache_transaction.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file declares HttpCache::Transaction, a private class of HttpCache so
 // it should only be included by http_cache.cc
 
 #ifndef NET_HTTP_HTTP_CACHE_TRANSACTION_H_
 #define NET_HTTP_HTTP_CACHE_TRANSACTION_H_
 
@@ skipping 156 matching lines @@
     STATE_CACHE_READ_METADATA,
     STATE_CACHE_READ_METADATA_COMPLETE,
     STATE_CACHE_QUERY_DATA,
     STATE_CACHE_QUERY_DATA_COMPLETE,
     STATE_CACHE_READ_DATA,
     STATE_CACHE_READ_DATA_COMPLETE,
     STATE_CACHE_WRITE_DATA,
     STATE_CACHE_WRITE_DATA_COMPLETE
   };
 
+  // Used for reporting times in histograms. The dispositions cover relatively
+  // common simple cases for cache resource requests, but are not intended to be
+  // exhaustive; many tricky special cases are all binned together as
+  // DISPOSITION_DO_NOT_RECORD.
+  enum Disposition {
+    DISPOSITION_UNDEFINED,
+    DISPOSITION_DO_NOT_RECORD,
+    DISPOSITION_NO_ENTRY,
+    DISPOSITION_ENTRY_UNCONDITIONALLY_USED,
+    DISPOSITION_ENTRY_VALIDATED_304,
+    DISPOSITION_ENTRY_VALIDATED_200,
+  };
+
   // This is a helper function used to trigger a completion callback.  It may
   // only be called if callback_ is non-null.
   void DoCallback(int rv);
 
   // This will trigger the completion callback if appropriate.
   int HandleResult(int rv);
 
   // Runs the state transition loop.
   int DoLoop(int result);
 
@@ skipping 140 matching lines @@
   int DoPartialCacheReadCompleted(int result);
 
   // Returns true if we should bother attempting to resume this request if it
   // is aborted while in progress. If |has_data| is true, the size of the stored
   // data is considered for the result.
   bool CanResume(bool has_data);
 
   // Called to signal completion of asynchronous IO.
   void OnIOComplete(int result);
 
+  // Called when we've determined the disposition of this request.
+  void MaybeUpdateDisposition(Disposition disposition);
+
+  // Called on completion of a request to record performance.
+  void RecordHistograms(int resource_size);
+
   State next_state_;
   const HttpRequestInfo* request_;
   BoundNetLog net_log_;
   scoped_ptr<HttpRequestInfo> custom_request_;
   HttpRequestHeaders request_headers_copy_;
   // If extra_headers specified a "if-modified-since" or "if-none-match",
   // |external_validation_| contains the value of those headers.
   ValidationHeaders external_validation_;
   base::WeakPtr<HttpCache> cache_;
   HttpCache::ActiveEntry* entry_;
-  base::TimeTicks entry_lock_waiting_since_;
   HttpCache::ActiveEntry* new_entry_;
   scoped_ptr<HttpTransaction> network_trans_;
   CompletionCallback callback_;  // Consumer's callback.
   HttpResponseInfo response_;
   HttpResponseInfo auth_response_;
   const HttpResponseInfo* new_response_;
   std::string cache_key_;
   Mode mode_;
   State target_state_;
   bool reading_;  // We are already reading.
   bool invalid_range_;  // We may bypass the cache for this request.
   bool truncated_;  // We don't have all the response data.
   bool is_sparse_;  // The data is stored in sparse byte ranges.
   bool range_requested_;  // The user requested a byte range.
   bool handling_206_;  // We must deal with this 206 response.
   bool cache_pending_;  // We are waiting for the HttpCache.
   bool done_reading_;
   scoped_refptr<IOBuffer> read_buf_;
   int io_buf_len_;
   int read_offset_;
   int effective_load_flags_;
   int write_len_;
   scoped_ptr<PartialData> partial_;  // We are dealing with range requests.
   uint64 final_upload_progress_;
   base::WeakPtrFactory<Transaction> weak_factory_;
   CompletionCallback io_callback_;
+
+  // Members used to track data for histograms.
+  Disposition disposition_;
+  base::TimeTicks entry_lock_waiting_since_;
+  base::TimeTicks open_entry_since_;
+  base::TimeTicks started_reading_since_;
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_CACHE_TRANSACTION_H_