Break down HTTPCache.Result metric by resource type

net/http/http_cache_transaction.cc

Index: net/http/http_cache_transaction.cc
diff --git a/net/http/http_cache_transaction.cc b/net/http/http_cache_transaction.cc
index 38da8f3bd7b0fc8a7492cef49a0666fd027c8668..a9c7f775305264c402fa680fd3be314c79b91b49 100644
--- a/net/http/http_cache_transaction.cc
+++ b/net/http/http_cache_transaction.cc
@@ -2704,6 +2704,27 @@ void HttpCache::Transaction::RecordHistograms() {
       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)