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..61fb183aeb934d1a2d2e374fff62f380389242e0 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 +16,8 @@
 #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_lofi_helper.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 +92,88 @@ 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 +196,8 @@ 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_);
@@ -174,26 +259,57 @@ void DataReductionProxyNetworkDelegate::OnBeforeSendProxyHeadersInternal(
     const net::ProxyInfo& proxy_info,
     net::HttpRequestHeaders* headers) {
   DCHECK(data_reduction_proxy_config_);
+  LoFiState lofi_state = LOFI_DEFAULT;
+
+  if (data_reduction_proxy_io_data_ &&
+      data_reduction_proxy_io_data_->lofi_helper() && request) {
+    DataReductionProxyLoFiHelper* lofi_helper =
+        data_reduction_proxy_io_data_->lofi_helper();
+    lofi_state = lofi_helper->lofi_state(request);
+
+    net::NetworkQualityEstimator* network_quality_estimator = nullptr;
+    if (request->context())
+      network_quality_estimator =
+          request->context()->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 Lo-Fi off on these requests.
+    if (lofi_state == LOFI_DEFAULT &&
+        (request->load_flags() & net::LOAD_MAIN_FRAME) == 0) {
+      lofi_state = LOFI_OFF;
+      lofi_helper->set_lofi_state(request, lofi_state);
+    }
+
+    if (lofi_state == LOFI_DEFAULT) {
+      lofi_state =
+          data_reduction_proxy_config_->ShouldTurnOnLoFiOnMainFrameRequest(
+              network_quality_estimator)
+              ? LOFI_ON
+              : LOFI_OFF;
+      lofi_helper->set_lofi_state(request, lofi_state);
+      if (params::IsLoFiSlowConnectionsOnlyViaFlags() ||
+          data_reduction_proxy_config_->IsIncludedInLoFiEnabledFieldTrial()) {
+        RecordAutoLoFiRequestHeaderStateChange(previous_state_lofi_on_,
+                                               lofi_state == LOFI_ON);
+      }
+    }
+
+    if ((request->load_flags() & net::LOAD_MAIN_FRAME) != 0) {
+      if (params::IsLoFiSlowConnectionsOnlyViaFlags() ||
+          data_reduction_proxy_config_->IsIncludedInLoFiEnabledFieldTrial()) {
+        previous_state_lofi_on_ = lofi_state == LOFI_ON;
+      }
 
-  // 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);
-    if (data_reduction_proxy_io_data_) {
-      data_reduction_proxy_io_data_->SetLoFiModeActiveOnMainFrame(
-          data_reduction_proxy_config_->ShouldUseLoFiHeaderForRequests());
+      // TODO(megjablon): Need to switch to per page.
+      data_reduction_proxy_io_data_->SetLoFiModeActiveOnMainFrame(lofi_state ==
+                                                                  LOFI_ON);
     }
   }
 
   if (data_reduction_proxy_request_options_) {
     data_reduction_proxy_request_options_->MaybeAddRequestHeader(
-        request, proxy_info.proxy_server(), headers);
+        request, proxy_info.proxy_server(), headers, lofi_state == LOFI_ON);
   }
 }
 
@@ -254,13 +370,13 @@ 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(),
+            data_reduction_proxy_io_data_->lofi_helper() &&
+            data_reduction_proxy_io_data_->lofi_helper()->lofi_state(request) ==
+                LOFI_ON,
         received_content_length, original_content_length, freshness_lifetime);
     experiments_stats_->RecordBytes(request->request_time(), request_type,
                                     received_content_length,