Split content script injections into multiple tasks

third_party/WebKit/public/web/WebScriptExecutionCallback.h

Index: third_party/WebKit/public/web/WebScriptExecutionCallback.h
diff --git a/third_party/WebKit/public/web/WebScriptExecutionCallback.h b/third_party/WebKit/public/web/WebScriptExecutionCallback.h
index 77dc14b0d29457770940cd08b835f0d9ecdb2989..7055d6c9bb06c0c45c49235d95e7abfe776430eb 100644
--- a/third_party/WebKit/public/web/WebScriptExecutionCallback.h
+++ b/third_party/WebKit/public/web/WebScriptExecutionCallback.h
@@ -20,6 +20,9 @@ class WebScriptExecutionCallback {
  public:
   virtual ~WebScriptExecutionCallback() {}
 
+  // Method to be invoked when the asynchronous script is about to execute.
+  virtual void willExecute() {}
+
   // Method to be invoked when the asynchronous script execution is complete.
   // After function call all objects in vector will be collected
   virtual void completed(const WebVector<v8::Local<v8::Value>>&) {}