Defer loads in new pages/frames if ScopedPageLoadDeferral is active

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

Index: third_party/WebKit/Source/core/loader/FrameLoader.cpp
diff --git a/third_party/WebKit/Source/core/loader/FrameLoader.cpp b/third_party/WebKit/Source/core/loader/FrameLoader.cpp
index f1aff24f70f0195ec8f20ae6326178d8892c8647..5dcd07bcd2a52559c7f7d6ffda40df0c950bb8ec 100644
--- a/third_party/WebKit/Source/core/loader/FrameLoader.cpp
+++ b/third_party/WebKit/Source/core/loader/FrameLoader.cpp
@@ -204,6 +204,11 @@ void FrameLoader::init()
     m_provisionalDocumentLoader->startLoadingMainResource();
     m_frame->document()->cancelParsing();
     m_stateMachine.advanceTo(FrameLoaderStateMachine::DisplayingInitialEmptyDocument);
+    // Self-suspend if created in an already deferred Page. Note that
+    // cancelParsing() may have already detached the frame, since it fires a JS
+    // event.
+    if (m_frame->page() && m_frame->page()->defersLoading())
+        setDefersLoading(true);

[dcheng, 2016/07/25 06:48:18]

This makes me pretty sad. When we initially create a Page, we don't actually
have a frame associated with it. Thus, we have to tell the page to self-defer
once the initial empty page is synchronously loaded.

I'm also uncertain of the correctness of doing it here: I believe
startLoadingMainResource() also runs events, including the iframe load event. I
think it's OK because the navigations will get scheduled, and the defers loading
call here will suspend them.. but it's pretty dodgy.

     takeObjectSnapshot();
 }