Revert 232376 "Revert 232342 "New prefetch histograms to get an ..."

Didn't break bot, undoing revert.

> Revert 232342 "New prefetch histograms to get an idea of how oft..."
> 
> Broke the Linux Chromium OS ASAN Tests(3) bot.
> 
> > New prefetch histograms to get an idea of how often prefetches happen,
> > what their success rate is, how often they're canceled, how long
> > they take to load, and how big they are.
> > 
> > BUG=303816
> > 
> > Review URL: https://codereview.chromium.org/50493005
> 
> TBR=jkarlin@google.com
> 
> Review URL: https://codereview.chromium.org/55993002

TBR=csharp@chromium.org

Review URL: https://codereview.chromium.org/56243002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232418 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 99 insertions, 0 deletions

diff --git a/content/browser/loader/resource_loader.cc b/content/browser/loader/resource_loader.cc
index a995259..0a7047d 100644
--- a/content/browser/loader/resource_loader.cc
+++ b/content/browser/loader/resource_loader.cc
@@ -30,6 +30,7 @@
 #include "net/base/load_flags.h"
 #include "net/http/http_response_headers.h"
 #include "net/ssl/client_cert_store.h"
+#include "net/url_request/url_request_status.h"
 #include "webkit/browser/appcache/appcache_interceptor.h"
 
 using base::TimeDelta;
@@ -630,6 +631,7 @@ void ResourceLoader::CompleteRead(int bytes_read) {
 
 void ResourceLoader::ResponseCompleted() {
   VLOG(1) << "ResponseCompleted: " << request_->url().spec();
+  RecordHistograms();
   ResourceRequestInfoImpl* info = GetRequestInfo();
 
   std::string security_info;
@@ -657,4 +659,37 @@ void ResourceLoader::CallDidFinishLoading() {
   delegate_->DidFinishLoading(this);
 }
 
+void ResourceLoader::RecordHistograms() {
+  ResourceRequestInfoImpl* info = GetRequestInfo();
+
+  if (info->GetResourceType() == ResourceType::PREFETCH) {
+    PrefetchStatus status = STATUS_UNDEFINED;
+    TimeDelta total_time = base::TimeTicks::Now() - request_->creation_time();
+
+    switch (request_->status().status()) {
+      case net::URLRequestStatus::SUCCESS:
+        if (request_->was_cached()) {
+          status = STATUS_SUCCESS_FROM_CACHE;
+          UMA_HISTOGRAM_TIMES("Net.Prefetch.TimeSpentPrefetchingFromCache",
+                              total_time);
+        } else {
+          status = STATUS_SUCCESS_FROM_NETWORK;
+          UMA_HISTOGRAM_TIMES("Net.Prefetch.TimeSpentPrefetchingFromNetwork",
+                              total_time);
+        }
+        break;
+      case net::URLRequestStatus::CANCELED:
+        status = STATUS_CANCELED;
+        UMA_HISTOGRAM_TIMES("Net.Prefetch.TimeBeforeCancel", total_time);
+        break;
+      case net::URLRequestStatus::IO_PENDING:
+      case net::URLRequestStatus::FAILED:
+        status = STATUS_UNDEFINED;
+        break;
+    }
+
+    UMA_HISTOGRAM_ENUMERATION("Net.Prefetch.Pattern", status, STATUS_MAX);
+  }
+}
+
 }  // namespace content
diff --git a/content/browser/loader/resource_loader.h b/content/browser/loader/resource_loader.h
index 8662cca..ca8b119 100644
--- a/content/browser/loader/resource_loader.h
+++ b/content/browser/loader/resource_loader.h
@@ -99,9 +99,21 @@ class CONTENT_EXPORT ResourceLoader : public net::URLRequest::Delegate,
   void CompleteRead(int bytes_read);
   void ResponseCompleted();
   void CallDidFinishLoading();
+  void RecordHistograms();
 
   bool is_deferred() const { return deferred_stage_ != DEFERRED_NONE; }
 
+  // Used for categorizing loading of prefetches for reporting in histograms.
+  // NOTE: This enumeration is used in histograms, so please do not add entries
+  // in the middle.
+  enum PrefetchStatus {
+    STATUS_UNDEFINED,
+    STATUS_SUCCESS_FROM_CACHE,
+    STATUS_SUCCESS_FROM_NETWORK,
+    STATUS_CANCELED,
+    STATUS_MAX,
+  };
+
   enum DeferredStage {
     DEFERRED_NONE,
     DEFERRED_START,
diff --git a/net/url_request/url_request_http_job.cc b/net/url_request/url_request_http_job.cc
index e6b39f6..564da62 100644
--- a/net/url_request/url_request_http_job.cc
+++ b/net/url_request/url_request_http_job.cc
@@ -1489,6 +1489,10 @@ void URLRequestHttpJob::RecordPerfHistograms(CompletionCause reason) {
     }
   }
 
+  if (request_info_.load_flags & LOAD_PREFETCH && !request_->was_cached())
+    UMA_HISTOGRAM_COUNTS("Net.Prefetch.PrefilterBytesReadFromNetwork",
+                         prefilter_bytes_read());
+
   start_time_ = base::TimeTicks();
 }
 
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 495308e..d66818d 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -8268,6 +8268,47 @@ other types of suffix sets.
   </details>
 </histogram>
 
+<histogram name="Net.Prefetch.Pattern" enum="PrefetchStatus">
+  <summary>
+    The completion status of prefetches that have finished loading.
+  </summary>
+  <details>
+    Measurement occurs at ResourceLoader::ResponseCompleted so requests canceled
+    before that point are not registered.
+
+    Note that &quot;success from cache&quot; means that the
+    UrlRequest::was_cached() was true, and &quot;success from network&quot;
+    means that was_cached() was false.  Validated results are considered cached,
+    even though a conditional network request is made.
+  </details>
+</histogram>
+
+<histogram name="Net.Prefetch.PrefilterBytesReadFromNetwork" units="bytes">
+  <summary>
+    Number of bytes read from the network on behalf of prefetch requests.  This
+    is prefilter, so before any decompression.
+  </summary>
+</histogram>
+
+<histogram name="Net.Prefetch.TimeBeforeCancel" units="milliseconds">
+  <summary>
+    Time spent on prefetch requests before the request was canceled.
+  </summary>
+</histogram>
+
+<histogram name="Net.Prefetch.TimeSpentPrefetchingFromCache"
+    units="milliseconds">
+  <summary>Time spent on prefetch requests when fetched from cache.</summary>
+</histogram>
+
+<histogram name="Net.Prefetch.TimeSpentPrefetchingFromNetwork"
+    units="milliseconds">
+  <summary>
+    Time spent on prefetch requests when fetched from the network, including
+    validation time.
+  </summary>
+</histogram>
+
 <histogram name="Net.Priority_High_Latency" units="milliseconds">
   <obsolete>
     Replaced by Net.Priority_High_Latency_b.
@@ -26263,6 +26304,13 @@ other types of suffix sets.
   <int value="1" label="The pre-connect triggered host was accessed"/>
 </enum>
 
+<enum name="PrefetchStatus" type="int">
+  <int value="0" label="undefined"/>
+  <int value="1" label="success from cache"/>
+  <int value="2" label="success from network"/>
+  <int value="3" label="canceled in-flight"/>
+</enum>
+
 <enum name="PrerenderFinalStatus" type="int">
   <int value="0" label="USED"/>
   <int value="1" label="TIMED_OUT"/>