predictors: Add prefetcher histograms for speculative prefetch.

chrome/browser/predictors/resource_prefetcher.cc

 // Copyright 2014 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 "chrome/browser/predictors/resource_prefetcher.h"
 
 #include <iterator>
 #include <utility>
 
+#include "base/metrics/histogram_macros.h"
 #include "base/trace_event/trace_event.h"
 #include "content/public/browser/browser_thread.h"
 #include "net/base/io_buffer.h"
 #include "net/base/load_flags.h"
 #include "net/base/request_priority.h"
 #include "net/url_request/url_request_context.h"
 #include "url/origin.h"
 
 namespace {
 
 // The size of the buffer used to read the resource.
 static const size_t kResourceBufferSizeBytes = 50000;
 
 }  // namespace
 
 namespace predictors {
 
 ResourcePrefetcher::ResourcePrefetcher(
     Delegate* delegate,
     const ResourcePrefetchPredictorConfig& config,
     const GURL& main_frame_url,
     const std::vector<GURL>& urls)
     : state_(INITIALIZED),
       delegate_(delegate),
       config_(config),
-      main_frame_url_(main_frame_url) {
+      main_frame_url_(main_frame_url),
+      prefetched_count_(0),
+      prefetched_bytes_(0) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 
   std::copy(urls.begin(), urls.end(), std::back_inserter(request_queue_));
 }
 
 ResourcePrefetcher::~ResourcePrefetcher() {}
 
 void ResourcePrefetcher::Start() {
   TRACE_EVENT_ASYNC_BEGIN0("browser", "ResourcePrefetcher::Prefetch", this);
   DCHECK(thread_checker_.CalledOnValidThread());
@@ skipping 46 matching lines @@
         request_queue_.erase(request_it);
       }
     }
   }
 
   // If the inflight_requests_ is empty, we can't launch any more. Finish.
   if (inflight_requests_.empty()) {
     CHECK(host_inflight_counts_.empty());
     CHECK(request_queue_.empty() || state_ == STOPPED);
 
+    UMA_HISTOGRAM_COUNTS_100(
+        internal::kResourcePrefetchPredictorPrefetchedCountHistogram,
+        prefetched_count_);
+    UMA_HISTOGRAM_COUNTS_10000(
+        internal::kResourcePrefetchPredictorPrefetchedSizeHistogram,
+        prefetched_bytes_ / 1024);
+
     state_ = FINISHED;
     delegate_->ResourcePrefetcherFinished(this);
   }
 }
 
 void ResourcePrefetcher::SendRequest(const GURL& url) {
   std::unique_ptr<net::URLRequest> url_request =
       delegate_->GetURLRequestContext()->CreateRequest(url, net::LOW, this);
   host_inflight_counts_[url.host()] += 1;
 
@@ skipping 30 matching lines @@
 
 void ResourcePrefetcher::ReadFullResponse(net::URLRequest* request) {
   int bytes_read = 0;
   do {
     scoped_refptr<net::IOBuffer> buffer(new net::IOBuffer(
         kResourceBufferSizeBytes));
     bytes_read = request->Read(buffer.get(), kResourceBufferSizeBytes);
     if (bytes_read == net::ERR_IO_PENDING) {
       return;
     } else if (bytes_read <= 0) {
+      if (bytes_read == 0)
+        RequestComplete(request);
       FinishRequest(request);
       return;
     }
 
   } while (bytes_read > 0);
 }
 
+void ResourcePrefetcher::RequestComplete(net::URLRequest* request) {
+  ++prefetched_count_;
+  prefetched_bytes_ += request->GetTotalReceivedBytes();
+
+  UMA_HISTOGRAM_ENUMERATION(
+      internal::kResourcePrefetchPredictorCachePatternHistogram,
+      request->response_info().cache_entry_status,
+      net::HttpResponseInfo::CacheEntryStatus::ENTRY_MAX);
+}
+
 void ResourcePrefetcher::OnReceivedRedirect(
     net::URLRequest* request,
     const net::RedirectInfo& redirect_info,
     bool* defer_redirect) {
   FinishRequest(request);
 }
 
 void ResourcePrefetcher::OnAuthRequired(net::URLRequest* request,
                                         net::AuthChallengeInfo* auth_info) {
   FinishRequest(request);
@@ skipping 31 matching lines @@
   if (bytes_read <= 0) {
     FinishRequest(request);
     return;
   }
 
   if (bytes_read > 0)
     ReadFullResponse(request);
 }
 
 }  // namespace predictors