Introduce callback interface for running Javascript asynchronously in the renderer.

content/public/browser/render_view_host.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 CONTENT_PUBLIC_BROWSER_RENDER_VIEW_HOST_H_
 #define CONTENT_PUBLIC_BROWSER_RENDER_VIEW_HOST_H_
 
-#include "base/values.h"
+#include "base/callback_forward.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/render_widget_host.h"
 #include "content/public/common/page_zoom.h"
 #include "content/public/common/stop_find_action.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebDragOperation.h"
 
 class FilePath;
 class GURL;
 struct WebDropData;
 
-namespace webkit_glue {
-struct WebPreferences;
-}
-
 namespace gfx {
 class Point;
 }
 
+namespace base {
+class Value;
+}
+
 namespace ui {
 struct SelectedFileInfo;
 }
 
 namespace WebKit {
 struct WebFindOptions;
 struct WebMediaPlayerAction;
 struct WebPluginAction;
 }
 
+namespace webkit_glue {
+struct WebPreferences;
+}
+
 namespace content {
 
 class ChildProcessSecurityPolicy;
 class RenderProcessHost;
 class RenderViewHostDelegate;
 class SessionStorageNamespace;
 class SiteInstance;
 struct CustomContextMenuContext;
 
 // A RenderViewHost is responsible for creating and talking to a RenderView
 // object in a child process. It exposes a high level API to users, for things
 // like loading pages, adjusting the display and other browser functionality,
 // which it translates into IPC messages sent over the IPC channel with the
 // RenderView. It responds to all IPC messages sent by that RenderView and
 // cracks them, calling a delegate object back with higher level types where
 // possible.
 //
 // The intent of this interface is to provide a view-agnostic communication
 // conduit with a renderer. This is so we can build HTML views not only as
 // WebContents (see WebContents for an example) but also as views, etc.
 class CONTENT_EXPORT RenderViewHost : virtual public RenderWidgetHost {
  public:
+  typedef base::Callback<void(const base::Value*)> JavascriptResultCallback;
+
   // Returns the RenderViewHost given its ID and the ID of its render process.
   // Returns NULL if the IDs do not correspond to a live RenderViewHost.
   static RenderViewHost* FromID(int render_process_id, int render_view_id);
 
   // Downcasts from a RenderWidgetHost to a RenderViewHost.  Required
   // because RenderWidgetHost is a virtual base class.
   static RenderViewHost* From(RenderWidgetHost* rwh);
 
   // Checks that the given renderer can request |url|, if not it sets it to
   // about:blank.
@@ skipping 95 matching lines @@
   // located at the given point.
   virtual void ExecuteMediaPlayerActionAtLocation(
       const gfx::Point& location,
       const WebKit::WebMediaPlayerAction& action) = 0;
 
   // Runs some javascript within the context of a frame in the page.
   virtual void ExecuteJavascriptInWebFrame(const string16& frame_xpath,
                                            const string16& jscript) = 0;
 
   // Runs some javascript within the context of a frame in the page. The result
-  // is sent back via the notification EXECUTE_JAVASCRIPT_RESULT.
+  // is sent back via the notification NOTIFICATION_EXECUTE_JAVASCRIPT_RESULT.
+  // This returns an int, used as a key to identify the corresponding
+  // notification.
+  // OBSOLETE. Use ExecuteJavascriptInWebFrameCallbackResult instead.
   virtual int ExecuteJavascriptInWebFrameNotifyResult(

[jam, 2013/01/03 20:53:02]

what's the plan for removing this? i.e. will it be done in a followup? same for
ExecuteJavascriptAndGetValue

[Avi (use Gerrit), 2013/01/03 21:01:53]

Both will be done in followups. I'm working on both CLs now.

       const string16& frame_xpath,
       const string16& jscript) = 0;
 
-  virtual Value* ExecuteJavascriptAndGetValue(const string16& frame_xpath,
-                                              const string16& jscript) = 0;
+  // Runs some javascript within the context of a frame in the page. The result
+  // is sent back via the provided callback.
+  virtual void ExecuteJavascriptInWebFrameCallbackResult(
+      const string16& frame_xpath,
+      const string16& jscript,
+      const JavascriptResultCallback& callback) = 0;
+
+  // Runs some javascript within the context of a frame in the page. A nested
+  // message loop is run to wait for the result, which is returned. THIS SHOULD
+  // ONLY BE USED BY TESTS. TODO(avi): Move into a test file.
+  virtual base::Value* ExecuteJavascriptAndGetValue(
+      const string16& frame_xpath,
+      const string16& jscript) = 0;
 
   // Tells the renderer to perform the given action on the plugin located at
   // the given point.
   virtual void ExecutePluginActionAtLocation(
       const gfx::Point& location, const WebKit::WebPluginAction& action) = 0;
 
   // Asks the renderer to exit fullscreen
   virtual void ExitFullscreen() = 0;
 
   // Finds text on a page.
@@ skipping 94 matching lines @@
                                const WebKit::WebFindOptions& options,
                                int* match_count,
                                int* active_ordinal) = 0;
 #endif
 
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_RENDER_VIEW_HOST_H_