Break down HTTPCache.Result metric by resource type

net/http/http_cache_transaction.cc

 // 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.
 
 #include "net/http/http_cache_transaction.h"
 
 #include "build/build_config.h"  // For OS_POSIX
 
 #if defined(OS_POSIX)
 #include <unistd.h>
@@ skipping 2686 matching lines @@
   transaction_pattern_ = new_transaction_pattern;
 }
 
 void HttpCache::Transaction::RecordHistograms() {
   DCHECK_NE(PATTERN_UNDEFINED, transaction_pattern_);
   if (!cache_.get() || !cache_->GetCurrentBackend() ||
       cache_->GetCurrentBackend()->GetCacheType() != DISK_CACHE ||
       cache_->mode() != NORMAL || request_->method != "GET") {
     return;
   }
+

[Deprecated (see juliatuttle), 2016/03/22 15:12:47]

Have you thought about examining the content-type header? It might be more
reliable.

[jkarlin, 2016/03/23 14:54:57]

Yes, that's better. Thanks!

+  std::string request_path = request_->url.path();
+  if (base::EndsWith(request_path, ".js",
+                     base::CompareCase::INSENSITIVE_ASCII)) {
+    UMA_HISTOGRAM_ENUMERATION("HttpCache.Pattern.JavaScript",
+                              transaction_pattern_, PATTERN_MAX);
+  } else if (base::EndsWith(request_path, ".css",
+                            base::CompareCase::INSENSITIVE_ASCII)) {
+    UMA_HISTOGRAM_ENUMERATION("HttpCache.Pattern.CSS", transaction_pattern_,
+                              PATTERN_MAX);
+  } else if (base::EndsWith(request_path, ".html",
+                            base::CompareCase::INSENSITIVE_ASCII)) {
+    UMA_HISTOGRAM_ENUMERATION("HttpCache.Pattern.HTML", transaction_pattern_,
+                              PATTERN_MAX);
+  } else if (base::EndsWith(request_path, ".jpg",
+                            base::CompareCase::INSENSITIVE_ASCII)) {
+    // .jpg doesn't cover all image types, but this should provide a rough idea
+    // of the cache patterns of images.
+    UMA_HISTOGRAM_ENUMERATION("HttpCache.Pattern.JPG", transaction_pattern_,
+                              PATTERN_MAX);
+  }
   UMA_HISTOGRAM_ENUMERATION(
       "HttpCache.Pattern", transaction_pattern_, PATTERN_MAX);
   if (transaction_pattern_ == PATTERN_NOT_COVERED)
     return;
   DCHECK(!range_requested_);
   DCHECK(!first_cache_access_since_.is_null());
 
   TimeDelta total_time = base::TimeTicks::Now() - first_cache_access_since_;
 
   UMA_HISTOGRAM_TIMES("HttpCache.AccessToDone", total_time);
@@ skipping 57 matching lines @@
     default:
       NOTREACHED();
   }
 }
 
 void HttpCache::Transaction::OnIOComplete(int result) {
   DoLoop(result);
 }
 
 }  // namespace net