[Blink] Modify SuspendableScriptExecutor to take a v8::Function

extensions/renderer/script_context.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef EXTENSIONS_RENDERER_SCRIPT_CONTEXT_H_
 #define EXTENSIONS_RENDERER_SCRIPT_CONTEXT_H_
 
 #include <memory>
 #include <string>
 #include <utility>
@@ skipping 100 matching lines @@
   // Runs |function| with appropriate scopes. Doesn't catch exceptions, callers
   // must do that if they want.
   //
   // USE THIS METHOD RATHER THAN v8::Function::Call WHEREVER POSSIBLE.
   v8::Local<v8::Value> CallFunction(const v8::Local<v8::Function>& function,
                                     int argc,
                                     v8::Local<v8::Value> argv[]) const;
   v8::Local<v8::Value> CallFunction(
       const v8::Local<v8::Function>& function) const;
 
+  // Safely calls the v8::Function, respecting the page load deferrer and
+  // possibly executing asynchronously.
+  // TODO(devlin): Remove the above variants in favor of this.

[dcheng, 2016/10/04 05:58:49]

Btw, do you estimate that this will be a lot of work if we're just trying to fix
extension code?

[Devlin, 2016/10/04 19:40:05]

It's hard to say until I really start in on it.  I think I ran into at least a
few cases where we relied on the result, which would need to be restructured. 
I'm hoping there aren't any where we synchronously return a result to an
extension, because that would be very difficult indeed.

+  void SafeCallFunction(const v8::Local<v8::Function>& function,
+                        int argc,
+                        v8::Local<v8::Value> argv[]);
+
   void DispatchEvent(const char* event_name, v8::Local<v8::Array> args) const;
 
   // Returns the availability of the API |api_name|.
   Feature::Availability GetAvailability(const std::string& api_name);
 
   // Returns a string description of the type of context this is.
   std::string GetContextTypeDescription() const;
 
   // Returns a string description of the effective type of context this is.
   std::string GetEffectiveContextTypeDescription() const;
@@ skipping 127 matching lines @@
   std::unique_ptr<Runner> runner_;
 
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(ScriptContext);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_RENDERER_SCRIPT_CONTEXT_H_