[Extensions] Isolate ExtensionFunction results_ and error_

chrome/browser/extensions/chrome_extension_function.h

Index: chrome/browser/extensions/chrome_extension_function.h
diff --git a/chrome/browser/extensions/chrome_extension_function.h b/chrome/browser/extensions/chrome_extension_function.h
index a556085562dbf13e8e890d95ba37327bc9d5243f..1319e7812aa5a68b74bea6638285babfb33f8023 100644
--- a/chrome/browser/extensions/chrome_extension_function.h
+++ b/chrome/browser/extensions/chrome_extension_function.h
@@ -54,16 +54,26 @@ class ChromeUIThreadExtensionFunction : public UIThreadExtensionFunction {
   // Same as above but uses WindowControllerList instead of BrowserList.
   extensions::WindowController* GetExtensionWindowController();
 
-  // Gets the "current" web contents if any. If there is no associated web
-  // contents then defaults to the foremost one.
+  // ExtensionFunction:
   content::WebContents* GetAssociatedWebContents() override;
+  void SetError(const std::string& error) override;
+  const std::string& GetError() const override;
+
+ protected:
+  ~ChromeUIThreadExtensionFunction() override;
 
   // Responds with success/failure. |results_| or |error_| should be set
   // accordingly.
   void SendResponse(bool success);
 
- protected:
-  ~ChromeUIThreadExtensionFunction() override;
+  // Sets a single Value as the results of the function.
+  void SetResult(std::unique_ptr<base::Value> result);
+
+  // Sets multiple Values as the results of the function.
+  void SetResultList(std::unique_ptr<base::ListValue> results);
+
+  std::unique_ptr<base::ListValue> results_;
+  std::string error_;

[lazyboy, 2016/09/30 01:16:05]

I'm finding this very hard to grok, can we use different name for these?
Probably an ugly name that suggests that this is temporary workaround (also
citing the bug# in comment) until RespondFoo only exclusively sets them.

[Devlin, 2016/09/30 18:29:09]

We can't name these something different, because existing Chrome* extension
function implementations directly access them (as "error_" and "results_").  The
main goal of this CL is to ensure that, as we convert to and write new extension
functions, we don't add new uses of these, but for now we need to keep the
current ones.

I've added a comment to that effect.

 
  private:
   ChromeExtensionFunctionDetails chrome_details_;