PlzNavigate: Move navigation-level mixed content checks to the browser.

third_party/WebKit/Source/core/loader/MixedContentChecker.cpp

Index: third_party/WebKit/Source/core/loader/MixedContentChecker.cpp
diff --git a/third_party/WebKit/Source/core/loader/MixedContentChecker.cpp b/third_party/WebKit/Source/core/loader/MixedContentChecker.cpp
index 07a1f26e6c670ceb59ad85387f3a6a1f7753d7aa..f2f8213e517b5a7ac39ba83a86198d3ed27e6b31 100644
--- a/third_party/WebKit/Source/core/loader/MixedContentChecker.cpp
+++ b/third_party/WebKit/Source/core/loader/MixedContentChecker.cpp
@@ -219,6 +219,13 @@ bool MixedContentChecker::shouldBlockFetch(
     ResourceRequest::RedirectStatus redirectStatus,
     const KURL& url,
     MixedContentChecker::ReportingStatus reportingStatus) {
+  // Frame-level loads are checked by the browser. No need to check them again
+  // here.
+  if (frame->settings()->browserSideNavigationEnabled() &&
+      frameType != WebURLRequest::FrameTypeNone) {
+    return false;
+  }
+
   Frame* effectiveFrame = effectiveFrameForFrameType(frame, frameType);
   Frame* mixedFrame =
       inWhichFrameIsContentMixed(effectiveFrame, frameType, url);