This adds in the ability for Chrome to generate windows with snapshots of all...

chrome/browser/renderer_host/render_widget_host.h

 // Copyright (c) 2009 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_RENDERER_HOST_RENDER_WIDGET_HOST_H_
 #define CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_H_
 
 #include <deque>
 
 #include "app/surface/transport_dib.h"
@@ skipping 187 matching lines @@
   void Focus();
   void Blur();
   void LostCapture();
 
   // Notifies the RenderWidgetHost that the View was destroyed.
   void ViewDestroyed();
 
   // Indicates if the page has finished loading.
   void SetIsLoading(bool is_loading);
 
+  // This tells the renderer to paint into a bitmap and return it,
+  // regardless of whether the tab is hidden or not.  It returns the
+  // bitmap scaled so it matches the requested size, so that the
+  // scaling happens on the rendering thread.  When the bitmap is
+  // ready, the renderer sends a PaintAtSizeACK to this host, and the
+  // painting observer is notified.  Note that this bypasses most of
+  // the update logic that is normally invoked, and doesn't put the
+  // results into the backing store.
+  void PaintAtSize(TransportDIB::Handle dib_handle, const gfx::Size& size);
+
   // Get access to the widget's backing store.  If a resize is in progress,
   // then the current size of the backing store may be less than the size of
   // the widget's view.  If you pass |force_create| as true, then the backing
   // store will be created if it doesn't exist. Otherwise, NULL will be returned
   // if the backing store doesn't already exist. It will also return NULL if the
   // backing store could not be created.
   BackingStore* GetBackingStore(bool force_create);
 
   // Allocate a new backing store of the given size. Returns NULL on failure
   // (for example, if we don't currently have a RenderWidgetHostView.)
@@ skipping 188 matching lines @@
  protected:
   // true if a renderer has once been valid. We use this flag to display a sad
   // tab only when we lose our renderer and not if a paint occurs during
   // initialization.
   bool renderer_initialized_;
 
  private:
   FRIEND_TEST(RenderWidgetHostTest, Resize);
   FRIEND_TEST(RenderWidgetHostTest, ResizeThenCrash);
   FRIEND_TEST(RenderWidgetHostTest, HiddenPaint);
+  FRIEND_TEST(RenderWidgetHostTest, PaintAtSize);
 
   // Tell this object to destroy itself.
   void Destroy();
 
   // Checks whether the renderer is hung and calls NotifyRendererUnresponsive
   // if it is.
   void CheckRendererIsUnresponsive();
 
-  // Called if we know the renderer is responsive. When we currently thing the
+  // Called if we know the renderer is responsive. When we currently think the
   // renderer is unresponsive, this will clear that state and call
   // NotifyRendererResponsive.
   void RendererIsResponsive();
 
   // IPC message handlers
   void OnMsgRenderViewReady();
   void OnMsgRenderViewGone();
   void OnMsgClose();
   void OnMsgRequestMove(const gfx::Rect& pos);
+  void OnMsgPaintAtSizeAck(const TransportDIB::Handle& dib_handle,
+                           const gfx::Size& size);
   void OnMsgUpdateRect(const ViewHostMsg_UpdateRect_Params& params);
   void OnMsgCreateVideo(const gfx::Size& size);
   void OnMsgUpdateVideo(TransportDIB::Id bitmap, const gfx::Rect& bitmap_rect);
   void OnMsgDestroyVideo();
   void OnMsgInputEventAck(const IPC::Message& message);
   void OnMsgFocus();
   void OnMsgBlur();
   virtual void OnMsgFocusedNodeChanged();
 
   void OnMsgSetCursor(const WebCursor& cursor);
@@ skipping 184 matching lines @@
   // changed.
   bool suppress_next_char_events_;
 
   // Optional video YUV layer for used for out-of-process compositing.
   scoped_ptr<VideoLayer> video_layer_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHost);
 };
 
 #endif  // CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_H_