Adds a crash key to V8EventListener to help diagnose crbug.com/621730 .

third_party/WebKit/Source/bindings/core/v8/V8EventListener.cpp

Index: third_party/WebKit/Source/bindings/core/v8/V8EventListener.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/V8EventListener.cpp b/third_party/WebKit/Source/bindings/core/v8/V8EventListener.cpp
index 017860884af8edf851e764f06149694d09abcff1..9a460ddeb0cf448e40230c7d999b84175ac0fcd8 100644
--- a/third_party/WebKit/Source/bindings/core/v8/V8EventListener.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/V8EventListener.cpp
@@ -33,7 +33,9 @@
 #include "bindings/core/v8/ScriptController.h"
 #include "bindings/core/v8/V8Binding.h"
 #include "core/dom/Document.h"
+#include "core/events/Event.h"
 #include "core/frame/LocalFrame.h"
+#include "wtf/debug/CrashLogging.h"
 
 namespace blink {
 
@@ -90,6 +92,28 @@ v8::Local<v8::Value> V8EventListener::callListenerFunction(ScriptState* scriptSt
     if (scriptState->world().isMainWorld() && !frame->script().canExecuteScripts(AboutToExecuteScript))
         return v8::Local<v8::Value>();
 
+    // Temporary instrumentation for http://crbug.com/621730.
+    String scriptInfo;
+    if (event->type() == EventTypeNames::message) {
+        v8::HandleScope handleScope(isolate());
+        StringBuilder scriptInfoBuilder;
+        V8StringResource<> functionName = handlerFunction->GetDebugName();
+        if (functionName.prepare()) {
+            scriptInfoBuilder.append(static_cast<String>(functionName));
+        }
+        scriptInfoBuilder.append(':');
+        scriptInfoBuilder.appendNumber(handlerFunction->GetScriptLineNumber());
+        scriptInfoBuilder.append(':');
+        scriptInfoBuilder.appendNumber(handlerFunction->GetScriptColumnNumber());
+        scriptInfoBuilder.append(':');
+        V8StringResource<> scriptName = handlerFunction->GetScriptOrigin().ResourceName();
+        if (scriptName.prepare()) {
+            scriptInfoBuilder.append(static_cast<String>(scriptName));
+        }
+        scriptInfo = scriptInfoBuilder.toString();
+    }
+    WTF::debug::ScopedCrashKey("postmessage_script_info", scriptInfo.utf8().data());
+
     v8::Local<v8::Value> parameters[1] = { jsEvent };
     v8::Local<v8::Value> result;
     if (!frame->script().callFunction(handlerFunction, receiver, WTF_ARRAY_LENGTH(parameters), parameters).ToLocal(&result))