Add a setting to strictly block "blockable" mixed content.

Source/web/WebSettingsImpl.cpp

Index: Source/web/WebSettingsImpl.cpp
diff --git a/Source/web/WebSettingsImpl.cpp b/Source/web/WebSettingsImpl.cpp
index f9de315cd44b6b3684d0db25e9be42154671e934..89b95d3c06635295b47cd02f07b79fd456acde46 100644
--- a/Source/web/WebSettingsImpl.cpp
+++ b/Source/web/WebSettingsImpl.cpp
@@ -619,6 +619,11 @@ void WebSettingsImpl::setStrictPowerfulFeatureRestrictions(bool enabled)
     m_settings->setStrictPowerfulFeatureRestrictions(enabled);
 }
 
+void WebSettingsImpl::setStrictlyBlockBlockableMixedContent(bool enabled)
+{
+    m_settings->setStrictlyBlockBlockableMixedContent(enabled);
+}
+
 void WebSettingsImpl::setPasswordEchoEnabled(bool flag)
 {
     m_settings->setPasswordEchoEnabled(flag);