Partial revert of r624035: always process JS urls in the window that requested the navigation

The spec says to use the target window, not the source window, but we have some bugs around
this targeting that may be breaking real websites. Temporary go back to the spec-violating
way, as the breakage appears to be smaller.

Bug: 935064
Change-Id: Ie1fd3030cbe8700820d1b8631bb3d318259e3380
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1504160
Commit-Queue: Nate Chapin <japhet@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Auto-Submit: Nate Chapin <japhet@chromium.org>
Cr-Commit-Position: refs/heads/master@{#637904}

third_party/blink/renderer/core/loader/frame_loader.cc

@@ -706,6 +706,10 @@ bool FrameLoader::PrepareRequestForThisFrame(FrameLoadRequest& request) {
 
     if (frame_->Owner() && frame_->Owner()->GetSandboxFlags() & kSandboxOrigin)
       return false;
+
+    frame_->GetDocument()->ProcessJavaScriptUrl(
+        url, request.ShouldCheckMainWorldContentSecurityPolicy());
+    return false;
   }
 
   if (!request.OriginDocument()->GetSecurityOrigin()->CanDisplay(url)) {
@@ -940,12 +944,6 @@ void FrameLoader::StartNavigation(const FrameLoadRequest& passed_request,
     LocalFrame::ConsumeTransientUserActivation(frame_);
   }
 
-  if (url.ProtocolIsJavaScript()) {
-    frame_->GetDocument()->ProcessJavaScriptUrl(
-        url, request.ShouldCheckMainWorldContentSecurityPolicy());
-    return;
-  }
-
   Client()->BeginNavigation(
       resource_request, origin_document, nullptr /* document_loader */,
       navigation_type, policy, has_transient_activation, frame_load_type,

third_party/blink/web_tests/TestExpectations

@@ -5956,6 +5956,11 @@ crbug.com/932078 virtual/outofblink-cors/http/tests/security/powerfulFeatureRest
 # Wasm threads enabled by default
 crbug.com/754910 virtual/origin-trials-runtimeflags-disabled/http/tests/origin_trials/webexposed/wasm-threads-origin-trial-disabled.html [ Skip ]
 
+# These tests depend on targeting javascript: url navigations at the specified window.
+crbug.com/935064 external/wpt/html/browsers/browsing-the-web/navigating-across-documents/javascript-url-abort/javascript-url-abort-return-value-string.tentative.html [ Failure ]
+crbug.com/935064 external/wpt/content-security-policy/inheritance/iframe-all-local-schemes.sub.html [ Failure ]
+crbug.com/935064 external/wpt/content-security-policy/unsafe-hashes/javascript_src_allowed-href_blank.html [ Timeout ]
+
 # Sheriff 2019-02-28
 crbug.com/936827 external/wpt/fullscreen/api/element-request-fullscreen-and-remove-manual.html [ Failure Pass ]