Added UMA to track bytes for cacheable resources

This includes a count of received bytes with associated freshness
lifetimes that are greater than 0, 4, and 24 hours, as well as
counts of resource retrievals by freshness lifetime.

BUG=249035

Review URL: https://chromiumcodereview.appspot.com/16838005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@207132 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 52 insertions, 2 deletions

diff --git a/chrome/browser/net/chrome_network_delegate.cc b/chrome/browser/net/chrome_network_delegate.cc
index fad14af..b43b53b 100644
--- a/chrome/browser/net/chrome_network_delegate.cc
+++ b/chrome/browser/net/chrome_network_delegate.cc
@@ -327,7 +327,8 @@ void StoreAccumulatedContentLength(int received_content_length,
 }
 
 void RecordContentLengthHistograms(
-    int64 received_content_length, int64 original_content_length) {
+    int64 received_content_length, int64 original_content_length,
+    const base::TimeDelta& freshness_lifetime) {
 #if defined(OS_ANDROID)
   // Add the current resource to these histograms only when a valid
   // X-Original-Content-Length header is present.
@@ -348,6 +349,23 @@ void RecordContentLengthHistograms(
                        original_content_length);
   UMA_HISTOGRAM_COUNTS("Net.HttpContentLengthDifference",
                        original_content_length - received_content_length);
+  UMA_HISTOGRAM_CUSTOM_TIMES("Net.HttpContentFreshnessLifetime",
+                             freshness_lifetime,
+                             base::TimeDelta::FromHours(1),
+                             base::TimeDelta::FromDays(30), 100);
+  if (freshness_lifetime.InSeconds() <= 0)
+    return;
+  UMA_HISTOGRAM_COUNTS("Net.HttpContentLengthCacheable",
+                       received_content_length);
+  if (freshness_lifetime.InHours() < 4)
+    return;
+  UMA_HISTOGRAM_COUNTS("Net.HttpContentLengthCacheable4Hours",
+                       received_content_length);
+
+  if (freshness_lifetime.InHours() < 24)
+    return;
+  UMA_HISTOGRAM_COUNTS("Net.HttpContentLengthCacheable24Hours",
+                       received_content_length);
 #endif
 }
 
@@ -566,10 +584,14 @@ void ChromeNetworkDelegate::OnCompleted(net::URLRequest* request,
       int64 adjusted_original_content_length = original_content_length;
       if (adjusted_original_content_length == -1)
         adjusted_original_content_length = received_content_length;
+      base::TimeDelta freshness_lifetime =
+          request->response_info().headers->GetFreshnessLifetime(
+              request->response_info().response_time);
       AccumulateContentLength(received_content_length,
                               adjusted_original_content_length);
       RecordContentLengthHistograms(received_content_length,
-                                    original_content_length);
+                                    original_content_length,
+                                    freshness_lifetime);
       DVLOG(2) << __FUNCTION__
           << " received content length: " << received_content_length
           << " original content length: " << original_content_length
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index b3b3e89..c36793f 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -4902,6 +4902,10 @@ other types of suffix sets.
   </summary>
 </histogram>
 
+<histogram name="Net.HttpContentFreshnessLifetime" units="milliseconds">
+  <summary>Length of time that a received resource will be cacheable.</summary>
+</histogram>
+
 <histogram name="Net.HttpContentLength" units="bytes">
   <summary>
     Size of the response body. This is the actual number of bytes received,
@@ -4910,6 +4914,30 @@ other types of suffix sets.
   </summary>
 </histogram>
 
+<histogram name="Net.HttpContentLengthCacheable" units="bytes">
+  <summary>
+    Size of the response body if it is cacheable. This is the actual number of
+    bytes received, which usually agrees with but is not necessarily the same as
+    the size specified by the Content-Length header.
+  </summary>
+</histogram>
+
+<histogram name="Net.HttpContentLengthCacheable24Hours" units="bytes">
+  <summary>
+    Size of the response body if it is cacheable for at least 24 hours. This is
+    the actual number of bytes received, which usually agrees with but is not
+    necessarily the same as the size specified by the Content-Length header.
+  </summary>
+</histogram>
+
+<histogram name="Net.HttpContentLengthCacheable4Hours" units="bytes">
+  <summary>
+    Size of the response body if it is cacheable for at least 4 hours. This is
+    the actual number of bytes received, which usually agrees with but is not
+    necessarily the same as the size specified by the Content-Length header.
+  </summary>
+</histogram>
+
 <histogram name="Net.HttpContentLengthDifference" units="bytes">
   <summary>
     The difference between the size specified in the X-Original-Content-Length