Mitigate the pushState IPC storm DoS.

third_party/WebKit/Source/core/frame/History.h

Index: third_party/WebKit/Source/core/frame/History.h
diff --git a/third_party/WebKit/Source/core/frame/History.h b/third_party/WebKit/Source/core/frame/History.h
index fb7fc5ea80e861f79ba6018f86a012daf1056201..4120d3c79366456565ee43846bc2627574c73e1d 100644
--- a/third_party/WebKit/Source/core/frame/History.h
+++ b/third_party/WebKit/Source/core/frame/History.h
@@ -33,6 +33,7 @@
 #include "platform/bindings/ScriptWrappable.h"
 #include "platform/heap/Handle.h"
 #include "platform/wtf/Forward.h"
+#include "platform/wtf/Time.h"
 
 namespace blink {
 
@@ -102,7 +103,13 @@ class CORE_EXPORT History final : public GarbageCollectedFinalized<History>,
   SerializedScriptValue* StateInternal() const;
   HistoryScrollRestorationType ScrollRestorationInternal() const;
 
+  bool IsThrottlingStateObjectChanges() const;

[dcheng, 2017/07/07 22:04:24]

Sorry. I thought about this slightly more and I think "ShouldThrottle" is better
than "IsThrottling" =P

I would also just not mark it const (since it really isn't)

[palmer, 2017/07/07 23:22:26]

OK. In the previous patchset I thought about calling it "ShouldThrottle" but
convinced myself that your name made sense as a reflection of the object's
internal policy-deciding state. But, whatever. :) I'll change it to
ShouldThrottle.
OK.

+
   RefPtr<SerializedScriptValue> last_state_object_requested_;
+  mutable struct {

[dcheng, 2017/07/07 22:04:24]

Then we won't need mutable!

[palmer, 2017/07/07 23:22:26]

OK.

+    int count;
+    TimeTicks last_updated;
+  } state_flood_guard;
 };
 
 }  // namespace blink