Consistently use LoFi for an entire page

components/data_reduction_proxy/core/browser/data_reduction_proxy_network_delegate.cc

Index: components/data_reduction_proxy/core/browser/data_reduction_proxy_network_delegate.cc
diff --git a/components/data_reduction_proxy/core/browser/data_reduction_proxy_network_delegate.cc b/components/data_reduction_proxy/core/browser/data_reduction_proxy_network_delegate.cc
index ff611f7f80a7ba10c00babf0390d47109a4d10a7..efc33daffdef93a6f052901fc146009e15314fe2 100644
--- a/components/data_reduction_proxy/core/browser/data_reduction_proxy_network_delegate.cc
+++ b/components/data_reduction_proxy/core/browser/data_reduction_proxy_network_delegate.cc
@@ -16,6 +16,7 @@
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_io_data.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_request_options.h"
 #include "components/data_reduction_proxy/core/common/data_reduction_proxy_event_creator.h"
+#include "components/data_reduction_proxy/core/common/data_reduction_proxy_params.h"
 #include "net/base/load_flags.h"
 #include "net/http/http_response_headers.h"
 #include "net/proxy/proxy_info.h"
@@ -90,6 +91,88 @@ void RecordContentLengthHistograms(bool lofi_low_header_added,
                        received_content_length);
 }
 
+// Following UMA is plotted to measure how frequently Lo-Fi state changes.
+// Too frequent changes are undesirable.
+void RecordAutoLoFiRequestHeaderStateChange(bool previous_header_low,
+                                            bool current_header_low) {
+  // Auto Lo-Fi request header state changes.
+  // Possible Lo-Fi header directives are empty ("") and low ("q=low").
+  // This enum must remain synchronized with the enum of the same name in
+  // metrics/histograms/histograms.xml.
+  enum AutoLoFiRequestHeaderState {
+    AUTO_LOFI_REQUEST_HEADER_STATE_EMPTY_TO_EMPTY = 0,
+    AUTO_LOFI_REQUEST_HEADER_STATE_EMPTY_TO_LOW = 1,
+    AUTO_LOFI_REQUEST_HEADER_STATE_LOW_TO_EMPTY = 2,
+    AUTO_LOFI_REQUEST_HEADER_STATE_LOW_TO_LOW = 3,
+    AUTO_LOFI_REQUEST_HEADER_STATE_INDEX_BOUNDARY
+  };
+
+  AutoLoFiRequestHeaderState state;
+  net::NetworkChangeNotifier::ConnectionType connection_type =
+      net::NetworkChangeNotifier::GetConnectionType();
+
+  if (!previous_header_low) {
+    if (current_header_low)
+      state = AUTO_LOFI_REQUEST_HEADER_STATE_EMPTY_TO_LOW;
+    else
+      state = AUTO_LOFI_REQUEST_HEADER_STATE_EMPTY_TO_EMPTY;
+  } else {
+    if (current_header_low) {
+      // Low to low in useful in checking how many consecutive page loads
+      // are done with Lo-Fi enabled.
+      state = AUTO_LOFI_REQUEST_HEADER_STATE_LOW_TO_LOW;
+    } else {
+      state = AUTO_LOFI_REQUEST_HEADER_STATE_LOW_TO_EMPTY;
+    }
+  }
+
+  switch (connection_type) {
+    case net::NetworkChangeNotifier::CONNECTION_UNKNOWN:
+      UMA_HISTOGRAM_ENUMERATION(
+          "DataReductionProxy.AutoLoFiRequestHeaderState.Unknown", state,
+          AUTO_LOFI_REQUEST_HEADER_STATE_INDEX_BOUNDARY);
+      break;
+    case net::NetworkChangeNotifier::CONNECTION_ETHERNET:
+      UMA_HISTOGRAM_ENUMERATION(
+          "DataReductionProxy.AutoLoFiRequestHeaderState.Ethernet", state,
+          AUTO_LOFI_REQUEST_HEADER_STATE_INDEX_BOUNDARY);
+      break;
+    case net::NetworkChangeNotifier::CONNECTION_WIFI:
+      UMA_HISTOGRAM_ENUMERATION(
+          "DataReductionProxy.AutoLoFiRequestHeaderState.WiFi", state,
+          AUTO_LOFI_REQUEST_HEADER_STATE_INDEX_BOUNDARY);
+      break;
+    case net::NetworkChangeNotifier::CONNECTION_2G:
+      UMA_HISTOGRAM_ENUMERATION(
+          "DataReductionProxy.AutoLoFiRequestHeaderState.2G", state,
+          AUTO_LOFI_REQUEST_HEADER_STATE_INDEX_BOUNDARY);
+      break;
+    case net::NetworkChangeNotifier::CONNECTION_3G:
+      UMA_HISTOGRAM_ENUMERATION(
+          "DataReductionProxy.AutoLoFiRequestHeaderState.3G", state,
+          AUTO_LOFI_REQUEST_HEADER_STATE_INDEX_BOUNDARY);
+      break;
+    case net::NetworkChangeNotifier::CONNECTION_4G:
+      UMA_HISTOGRAM_ENUMERATION(
+          "DataReductionProxy.AutoLoFiRequestHeaderState.4G", state,
+          AUTO_LOFI_REQUEST_HEADER_STATE_INDEX_BOUNDARY);
+      break;
+    case net::NetworkChangeNotifier::CONNECTION_NONE:
+      UMA_HISTOGRAM_ENUMERATION(
+          "DataReductionProxy.AutoLoFiRequestHeaderState.None", state,
+          AUTO_LOFI_REQUEST_HEADER_STATE_INDEX_BOUNDARY);
+      break;
+    case net::NetworkChangeNotifier::CONNECTION_BLUETOOTH:
+      UMA_HISTOGRAM_ENUMERATION(
+          "DataReductionProxy.AutoLoFiRequestHeaderState.Bluetooth", state,
+          AUTO_LOFI_REQUEST_HEADER_STATE_INDEX_BOUNDARY);
+      break;
+    default:
+      NOTREACHED();
+      break;
+  }
+}
+
 }  // namespace
 
 namespace data_reduction_proxy {
@@ -112,7 +195,8 @@ DataReductionProxyNetworkDelegate::DataReductionProxyNetworkDelegate(
       configurator_(configurator),
       experiments_stats_(experiments_stats),
       net_log_(net_log),
-      event_creator_(event_creator) {
+      event_creator_(event_creator),
+      previous_state_lofi_on_(false) {
   DCHECK(data_reduction_proxy_config_);
   DCHECK(data_reduction_proxy_request_options_);
   DCHECK(configurator_);
@@ -175,19 +259,38 @@ void DataReductionProxyNetworkDelegate::OnBeforeSendProxyHeadersInternal(
     net::HttpRequestHeaders* headers) {
   DCHECK(data_reduction_proxy_config_);
 
-  // TODO(bengr): Investigate a better approach to update the network
-  // quality so that state of Lo-Fi is stored per page.
   net::NetworkQualityEstimator* network_quality_estimator = nullptr;
   if (request && request->context())
     network_quality_estimator = request->context()->network_quality_estimator();
 
-  if (request && ((request->load_flags() & net::LOAD_MAIN_FRAME) != 0)) {
-    data_reduction_proxy_config_->UpdateLoFiStatusOnMainFrameRequest(
-        ((request->load_flags() & net::LOAD_BYPASS_CACHE) != 0),
-        network_quality_estimator);
+  // Some requests, such as pings, don't go through
+  // RenderFrameImpl::WillSendRequest and get the LoFi state since they outlive
+  // the parent document. Set LoFi off on these requests.
+  if (request && request->lofi_state() == net::LOFI_DEFAULT &&
+      (request->load_flags() & net::LOAD_MAIN_FRAME) == 0) {
+    request->set_lofi_state(net::LOFI_OFF);
+  }
+
+  if (request && request->lofi_state() == net::LOFI_DEFAULT) {
+    request->set_lofi_state(
+        data_reduction_proxy_config_->ShouldTurnOnLoFiOnMainFrameRequest(
+            network_quality_estimator)
+            ? net::LOFI_ON
+            : net::LOFI_OFF);
+    if (params::IsLoFiSlowConnectionsOnlyViaFlags() ||
+        data_reduction_proxy_config_->IsIncludedInLoFiEnabledFieldTrial()) {
+      RecordAutoLoFiRequestHeaderStateChange(
+          previous_state_lofi_on_, request->lofi_state() == net::LOFI_ON);
+    }
+  }
+
+  if (request && (request->load_flags() & net::LOAD_MAIN_FRAME) != 0) {
+    previous_state_lofi_on_ = request->lofi_state() == net::LOFI_ON;
+
     if (data_reduction_proxy_io_data_) {
+      // TODO(megjablon): Need to switch to per page.
       data_reduction_proxy_io_data_->SetLoFiModeActiveOnMainFrame(
-          data_reduction_proxy_config_->ShouldUseLoFiHeaderForRequests());
+          request->lofi_state() == net::LOFI_ON);
     }
   }
 
@@ -254,13 +357,11 @@ void DataReductionProxyNetworkDelegate::OnCompletedInternal(
 
     DCHECK(data_reduction_proxy_config_);
 
-    // TODO(bengr): Investigate a better approach to record the Lo-Fi
-    // histogram. State of Lo-Fi should be stored per page.
     RecordContentLengthHistograms(
         // |data_reduction_proxy_io_data_| can be NULL for Webview.
         data_reduction_proxy_io_data_ &&
             data_reduction_proxy_io_data_->IsEnabled() &&
-            data_reduction_proxy_config_->ShouldUseLoFiHeaderForRequests(),
+            request->lofi_state() == net::LOFI_ON,
         received_content_length, original_content_length, freshness_lifetime);
     experiments_stats_->RecordBytes(request->request_time(), request_type,
                                     received_content_length,