Add crash keys to LocalDOMWindow to help diagnose bug 621730.

third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp

Index: third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
diff --git a/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp b/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
index 130fa525436b6c9a99074fab4f406eab4484d746..3fb2487fc82f15bdd6117ebec24276a9d4c7bf0a 100644
--- a/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
+++ b/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
@@ -26,6 +26,7 @@
 
 #include "core/frame/LocalDOMWindow.h"
 
+#include "base/debug/crash_logging.h"
 #include "bindings/core/v8/ScriptController.h"
 #include "bindings/core/v8/SourceLocation.h"
 #include "core/css/CSSComputedStyleDeclaration.h"
@@ -687,6 +688,11 @@ void LocalDOMWindow::postMessageTimerFired(PostMessageTimer* timer)
     UserGestureIndicator gestureIndicator(timer->userGestureToken());
 
     event->entangleMessagePorts(document());
+
+    // Temporary instrumentation for http://crbug.com/621730.
+    base::debug::ScopedCrashKey("postmessage_src_origin", event->origin().utf8().data());
+    base::debug::ScopedCrashKey("postmessage_dst_origin", document()->getSecurityOrigin()->toRawString().utf8().data());
+    base::debug::ScopedCrashKey("postmessage_dst_url", document()->url().getString().utf8().data());
     dispatchMessageEventWithOriginCheck(timer->targetOrigin(), event, timer->takeLocation());
 }