Dev tools warning and console warning for document.write script blocking

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

Index: third_party/WebKit/Source/core/loader/FrameFetchContext.cpp
diff --git a/third_party/WebKit/Source/core/loader/FrameFetchContext.cpp b/third_party/WebKit/Source/core/loader/FrameFetchContext.cpp
index c08ee5f31a0503f3eaff2cf213ad4023c961e87e..a1dff2a3b909478411e4faa936f6eddc4d6ca9a2 100644
--- a/third_party/WebKit/Source/core/loader/FrameFetchContext.cpp
+++ b/third_party/WebKit/Source/core/loader/FrameFetchContext.cpp
@@ -76,19 +76,24 @@
 
 namespace blink {
 
-namespace {
+void FrameFetchContext::emitWarningForDocWriteScripts(const String& url) const

[Nate Chapin, 2016/06/09 23:44:44]

Maybe take the a const Document& here and keep this and
shouldDisallowFetchForMainFrameScript() file-scope?

+{
+    String message = "A Parser-blocking, cross-origin script " + url + " is invoked via document.write. This may get blocked by the browser in slow connections. It is recommended to invoke this script asynchronously.";
+    addConsoleMessage(message, WarningMessageLevel);

[Nate Chapin, 2016/06/09 23:44:44]

Call frame()->document()->addConsoleMessage() directly here? The overloaded
addConsoleMessage() helper doesn't seem worthwhile.

[shivanisha, 2016/06/10 14:41:01]

Sounds good. Made these changes.

+    WTFLogAlways("%s", message.utf8().data());
+}
 
-bool shouldDisallowFetchForMainFrameScript(const ResourceRequest& request, FetchRequest::DeferOption defer, const Document& document)
+bool FrameFetchContext::shouldDisallowFetchForMainFrameScript(const ResourceRequest& request, FetchRequest::DeferOption defer) const
 {
     // Only scripts inserted via document.write are candidates for having their
     // fetch disallowed.
-    if (!document.isInDocumentWrite())
+    if (!m_document->isInDocumentWrite())
         return false;
 
-    if (!document.settings())
+    if (!m_document->settings())
         return false;
 
-    if (!document.frame())
+    if (!m_document->frame())
         return false;
 
     // Only block synchronously loaded (parser blocking) scripts.
@@ -101,34 +106,34 @@ bool shouldDisallowFetchForMainFrameScript(const ResourceRequest& request, Fetch
     // Avoid blocking same origin scripts, as they may be used to render main
     // page content, whereas cross-origin scripts inserted via document.write
     // are likely to be third party content.
-    if (request.url().host() == document.getSecurityOrigin()->domain())
+    if (request.url().host() == m_document->getSecurityOrigin()->domain())
         return false;
 
     // Do not block scripts if it is a page reload. This is to enable pages to
     // recover if blocking of a script is leading to a page break and the user
     // reloads the page.
-    const FrameLoadType loadType = document.frame()->loader().loadType();
+    const FrameLoadType loadType = m_document->frame()->loader().loadType();
     const bool isReload = loadType == FrameLoadTypeReload || loadType == FrameLoadTypeReloadBypassingCache || loadType == FrameLoadTypeReloadMainResource;
     if (isReload) {
         // Recording this metric since an increase in number of reloads for pages
         // where a script was blocked could be indicative of a page break.
-        document.loader()->didObserveLoadingBehavior(WebLoadingBehaviorFlag::WebLoadingBehaviorDocumentWriteBlockReload);
+        m_document->loader()->didObserveLoadingBehavior(WebLoadingBehaviorFlag::WebLoadingBehaviorDocumentWriteBlockReload);
         return false;
     }
 
     // Add the metadata that this page has scripts inserted via document.write
     // that are eligible for blocking. Note that if there are multiple scripts
     // the flag will be conveyed to the browser process only once.
-    document.loader()->didObserveLoadingBehavior(WebLoadingBehaviorFlag::WebLoadingBehaviorDocumentWriteBlock);
+    m_document->loader()->didObserveLoadingBehavior(WebLoadingBehaviorFlag::WebLoadingBehaviorDocumentWriteBlock);
+
+    emitWarningForDocWriteScripts(request.url().getString());
 
     const bool isSlowConnection = networkStateNotifier().connectionType() == WebConnectionTypeCellular2G;
-    const bool disallowFetch = document.settings()->disallowFetchForDocWrittenScriptsInMainFrame() || (document.settings()->disallowFetchForDocWrittenScriptsInMainFrameOnSlowConnections() && isSlowConnection);
+    const bool disallowFetch = m_document->settings()->disallowFetchForDocWrittenScriptsInMainFrame() || (m_document->settings()->disallowFetchForDocWrittenScriptsInMainFrameOnSlowConnections() && isSlowConnection);
 
     return disallowFetch;
 }
 
-} // namespace
-
 FrameFetchContext::FrameFetchContext(DocumentLoader* loader, Document* document)
     : m_document(document)
     , m_documentLoader(loader)
@@ -258,7 +263,7 @@ WebCachePolicy FrameFetchContext::resourceRequestCachePolicy(const ResourceReque
     // For users on slow connections, we want to avoid blocking the parser in
     // the main frame on script loads inserted via document.write, since it can
     // add significant delays before page content is displayed on the screen.
-    if (type == Resource::Script && isMainFrame() && m_document && shouldDisallowFetchForMainFrameScript(request, defer, *m_document))
+    if (type == Resource::Script && isMainFrame() && m_document && shouldDisallowFetchForMainFrameScript(request, defer))
         return WebCachePolicy::ReturnCacheDataDontLoad;
 
     if (request.isConditional())
@@ -632,6 +637,12 @@ void FrameFetchContext::sendImagePing(const KURL& url)
     PingLoader::loadImage(frame(), url);
 }
 
+void FrameFetchContext::addConsoleMessage(const String& message, MessageLevel level) const
+{
+    if (frame()->document())
+        frame()->document()->addConsoleMessage(ConsoleMessage::create(JSMessageSource, level, message));
+}
+
 void FrameFetchContext::addConsoleMessage(const String& message) const
 {
     if (frame()->document())