Separate validation failures from other failures in ExecuteCodeFunction.

chrome/browser/extensions/api/tabs/tabs_api.h

 // Copyright (c) 2012 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 CHROME_BROWSER_EXTENSIONS_API_TABS_TABS_API_H_
 #define CHROME_BROWSER_EXTENSIONS_API_TABS_TABS_API_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 216 matching lines @@
 class ExecuteCodeInTabFunction : public ExecuteCodeFunction {
  public:
   ExecuteCodeInTabFunction();
 
  protected:
   ~ExecuteCodeInTabFunction() override;
 
   // ExtensionFunction:
   bool HasPermission() override;
 
-  // Initialize the |execute_tab_id_| and |details_| if they haven't already
-  // been. Returns whether initialization was successful.
-  bool Init() override;
+  // Initializes |execute_tab_id_| and |details_|.
+  InitResult Init() override;
   bool CanExecuteScriptOnPage() override;
   ScriptExecutor* GetScriptExecutor() override;
   bool IsWebView() const override;
   const GURL& GetWebViewSrc() const override;
 
  private:
   const ChromeExtensionFunctionDetails chrome_details_;
 
   // Id of tab which executes code.
   int execute_tab_id_;
@@ skipping 82 matching lines @@
 
   // ExtensionFunction:
   ExtensionFunction::ResponseAction Run() override;
 
   DISALLOW_COPY_AND_ASSIGN(TabsDiscardFunction);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_TABS_TABS_API_H_