Mixed Content: Make MixedContentChecker completely static.

Source/core/loader/PingLoader.cpp

Index: Source/core/loader/PingLoader.cpp
diff --git a/Source/core/loader/PingLoader.cpp b/Source/core/loader/PingLoader.cpp
index 56f452e9687d13300b5cf01aeb28b32f4f6d7d06..e6c47398a11bf20b38a5d21fa0e22d065b8c7f79 100644
--- a/Source/core/loader/PingLoader.cpp
+++ b/Source/core/loader/PingLoader.cpp
@@ -40,6 +40,7 @@
 #include "core/inspector/InspectorTraceEvents.h"
 #include "core/loader/FrameLoader.h"
 #include "core/loader/FrameLoaderClient.h"
+#include "core/loader/MixedContentChecker.h"
 #include "core/loader/UniqueIdentifier.h"
 #include "core/page/Page.h"
 #include "platform/exported/WrappedResourceRequest.h"
@@ -121,7 +122,7 @@ void PingLoader::sendViolationReport(LocalFrame* frame, const KURL& reportURL, P
 
 void PingLoader::start(LocalFrame* frame, ResourceRequest& request, const FetchInitiatorInfo& initiatorInfo, StoredCredentials credentialsAllowed)
 {
-    if (!frame->loader().mixedContentChecker()->canRunInsecureContent(frame->document()->securityOrigin(), request.url()))
+    if (MixedContentChecker::shouldBlockFetch(frame, request.requestContext(), request.frameType(), request.url()))
         return;
 
     OwnPtr<PingLoader> pingLoader = adoptPtr(new PingLoader(frame, request, initiatorInfo, credentialsAllowed));