Introduce a field trial to strictly block "blockable" mixed content.

content/renderer/render_view_impl.cc

 // Copyright (c) 2012 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 "content/renderer/render_view_impl.h"
 
 #include <algorithm>
 #include <cmath>
 
 #include "base/auto_reset.h"
@@ skipping 1046 matching lines @@
   // Tabs to link is not part of the settings. WebCore calls
   // ChromeClient::tabsToLinks which is part of the glue code.
   web_view->setTabsToLinks(prefs.tabs_to_links);
 
   settings->setAllowDisplayOfInsecureContent(
       prefs.allow_displaying_insecure_content);
   settings->setAllowRunningOfInsecureContent(
       prefs.allow_running_insecure_content);
   settings->setDisableReadingFromCanvas(prefs.disable_reading_from_canvas);
   settings->setStrictMixedContentChecking(prefs.strict_mixed_content_checking);
+
+  settings->setStrictlyBlockBlockableMixedContent(
+      prefs.strictly_block_blockable_mixed_content);
+
   settings->setStrictPowerfulFeatureRestrictions(
       prefs.strict_powerful_feature_restrictions);
   settings->setPasswordEchoEnabled(prefs.password_echo_enabled);
   settings->setShouldPrintBackgrounds(prefs.should_print_backgrounds);
   settings->setShouldClearDocumentBackground(
       prefs.should_clear_document_background);
   settings->setEnableScrollAnimator(prefs.enable_scroll_animator);
 
   WebRuntimeFeatures::enableTouch(prefs.touch_enabled);
   settings->setMaxTouchPoints(prefs.pointer_events_max_touch_points);
@@ skipping 2734 matching lines @@
     std::vector<gfx::Size> sizes;
     ConvertToFaviconSizes(icon_urls[i].sizes(), &sizes);
     if (!url.isEmpty())
       urls.push_back(
           FaviconURL(url, ToFaviconType(icon_urls[i].iconType()), sizes));
   }
   SendUpdateFaviconURL(urls);
 }
 
 }  // namespace content