Deal with frame removal by content scripts

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 cf68d9d95c3a6e7632bd32b298ac6a5ded7121f8..5e680a685cc2a2ac94f617930dcaa8bad463c60a 100644
--- a/third_party/WebKit/Source/core/loader/FrameLoader.cpp
+++ b/third_party/WebKit/Source/core/loader/FrameLoader.cpp
@@ -37,9 +37,11 @@
 #include "bindings/core/v8/DOMWrapperWorld.h"
 #include "bindings/core/v8/ScriptController.h"
 #include "bindings/core/v8/SerializedScriptValue.h"
+#include "bindings/core/v8/V8PerIsolateData.h"
 #include "core/HTMLNames.h"
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
+#include "core/dom/Microtask.h"
 #include "core/dom/ViewportDescription.h"
 #include "core/editing/Editor.h"
 #include "core/editing/commands/UndoStack.h"
@@ -488,8 +490,12 @@ void FrameLoader::finishedParsing()
 
     m_progressTracker->finishedParsing();
 
-    if (client())
+    if (client()) {
         client()->dispatchDidFinishDocumentLoad(m_documentLoader ? m_documentLoader->isCommittedButEmpty() : true);
+        Microtask::performCheckpoint(V8PerIsolateData::mainThreadIsolate());
+        if (!m_frame->view())
+            return;
+    }
 
     checkCompleted();
 
@@ -1485,7 +1491,16 @@ bool FrameLoader::shouldTreatURLAsSrcdocDocument(const KURL& url) const
 
 void FrameLoader::dispatchDocumentElementAvailable()
 {
+    // TODO(robwu): Use ScriptForbiddenScope to prevent scripts from being run
+    // synchronously in documentElementAvailable.
     client()->documentElementAvailable();
+
+    // Run queued microtasks (scheduled by clients of documentElementAvailable),
+    // to make sure that the scripts run before the parser continues. This may
+    // result in a detached frame.
+    // If this method is called re-entrantly, then the microtask is deferred to
+    // the next microtask checkpoint.
+    Microtask::performCheckpoint(V8PerIsolateData::mainThreadIsolate());
 }
 
 void FrameLoader::dispatchDidClearDocumentOfWindowObject()