Lo-Fi snackbar should only be shown for the first q=low response of a page

chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_io_data.cc

 // Copyright 2015 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/net/spdyproxy/data_reduction_proxy_chrome_io_data.h"
 
 #include <utility>
 
+#include "base/bind.h"
 #include "base/prefs/pref_service.h"
 #include "build/build_config.h"
 #include "chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.h"
 #include "chrome/common/chrome_content_client.h"
 #include "chrome/common/pref_names.h"
 #include "components/data_reduction_proxy/content/browser/content_lofi_decider.h"
+#include "components/data_reduction_proxy/content/browser/content_lofi_ui_service.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_config_retrieval_params.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_experiments_stats.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_io_data.h"
 #include "components/data_reduction_proxy/core/common/data_reduction_proxy_params.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/web_contents.h"
 
 #if defined(OS_ANDROID)
 #include "base/android/build_info.h"
+#include "chrome/browser/android/tab_android.h"
 #endif
 
 #if defined(ENABLE_DATA_REDUCTION_PROXY_DEBUGGING)
 #include "chrome/browser/browser_process.h"
 #include "components/data_reduction_proxy/content/browser/content_data_reduction_proxy_debug_ui_service.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_configurator.h"
 #endif
 
 namespace content {
 class BrowserContext;
 }
 
 using data_reduction_proxy::DataReductionProxyParams;
 
+namespace {
+
+// Notifies the TabAndroid associated with |web_contents| that a Lo-Fi response

[tbansal1, 2016/01/05 21:07:09]

Rewrite the comment so that it is clear that this function does X for OS_ANDROID
and nothing for other platforms.

[megjablon, 2016/01/06 17:20:47]

Done.

+// has been received. The TabAndroid then handles showing Lo-Fi UI if this is
+// the first Lo-Fi response for a page load.
+void NotifyLoFiResponseReceivedOnUI(content::WebContents* web_contents) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+#if defined(OS_ANDROID)
+  TabAndroid* tab = TabAndroid::FromWebContents(web_contents);
+  if (tab)
+    tab->NotifyLoFiResponseReceived();
+#endif
+}
+
+} // namespace
+
 scoped_ptr<data_reduction_proxy::DataReductionProxyIOData>
 CreateDataReductionProxyChromeIOData(
     net::NetLog* net_log,
     PrefService* prefs,
     const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner,
     const scoped_refptr<base::SingleThreadTaskRunner>& ui_task_runner,
     bool enable_quic) {
   DCHECK(net_log);
   DCHECK(prefs);
 
@@ skipping 18 matching lines @@
           new data_reduction_proxy::DataReductionProxyIOData(
               DataReductionProxyChromeSettings::GetClient(), flags, net_log,
               io_task_runner, ui_task_runner, enabled, enable_quic,
               GetUserAgent()));
   data_reduction_proxy_io_data->experiments_stats()->InitializeOnUIThread(
       data_reduction_proxy::DataReductionProxyConfigRetrievalParams::Create(
           prefs));
 
   data_reduction_proxy_io_data->set_lofi_decider(
       make_scoped_ptr(new data_reduction_proxy::ContentLoFiDecider()));
+  data_reduction_proxy_io_data->set_lofi_ui_service(
+      make_scoped_ptr(new data_reduction_proxy::ContentLoFiUIService(
+          ui_task_runner,
+          base::Bind(&NotifyLoFiResponseReceivedOnUI))));
 
 #if defined(ENABLE_DATA_REDUCTION_PROXY_DEBUGGING)
   scoped_ptr<data_reduction_proxy::ContentDataReductionProxyDebugUIService>
       data_reduction_proxy_ui_service(
           new data_reduction_proxy::ContentDataReductionProxyDebugUIService(
               base::Bind(&data_reduction_proxy::DataReductionProxyConfigurator::
                              GetProxyConfig,
                          base::Unretained(
                              data_reduction_proxy_io_data->configurator())),
               ui_task_runner, io_task_runner,
               g_browser_process->GetApplicationLocale()));
   data_reduction_proxy_io_data->set_debug_ui_service(
       std::move(data_reduction_proxy_ui_service));
 #endif
 
   return data_reduction_proxy_io_data;
 }