Windows: Add off-screen rendering support (issue #518).

- Popup menus, drag&drop and GPU acceleration are not currently supported.
- Testing is enabled in cefclient by passing the "off-screen-rendering-enabled" command-line flag.

git-svn-id: https://chromiumembedded.googlecode.com/svn/trunk@919 5089003a-bbd8-11dd-ad1f-f1f9622dbc98

libcef/browser/browser_context.h

@@ -49,6 +49,13 @@ class CefBrowserContext : public content::BrowserContext {
       GetSpeechRecognitionPreferences() OVERRIDE;
   virtual quota::SpecialStoragePolicy* GetSpecialStoragePolicy() OVERRIDE;
 
+  // To disable window rendering call this function with |override|=true
+  // just before calling WebContents::Create. This will cause
+  // CefContentBrowserClient::OverrideCreateWebContentsView to create
+  // a windowless WebContentsView object.
+  void set_use_osr_next_contents_view(bool override);
+  bool use_osr_next_contents_view() const;
+
  private:
 
   scoped_ptr<CefResourceContext> resource_context_;
@@ -59,6 +66,8 @@ class CefBrowserContext : public content::BrowserContext {
   scoped_refptr<content::SpeechRecognitionPreferences>
       speech_recognition_preferences_;
 
+  bool use_osr_next_contents_view_;
+
   DISALLOW_COPY_AND_ASSIGN(CefBrowserContext);
 };