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

app/surface/transport_dib.h

 // Copyright (c) 2010 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 APP_SURFACE_TRANSPORT_DIB_H_
 #define APP_SURFACE_TRANSPORT_DIB_H_
 
 #include "base/basictypes.h"
 
 #if defined(OS_WIN) || defined(OS_MACOSX)
@@ skipping 55 matching lines @@
     }
 
     HANDLE handle;
     uint32 sequence_num;
   };
   typedef HandleAndSequenceNum Id;
 
   // Returns a default, invalid handle, that is meant to indicate a missing
   // Transport DIB.
   static Handle DefaultHandleValue() { return NULL; }
+
+  // Returns a value that is ONLY USEFUL FOR TESTS WHERE IT WON'T BE
+  // ACTUALLY USED AS A REAL HANDLE.
+  static Handle GetFakeHandleForTest() {
+    static int fake_handle = 10;
+    return reinterpret_cast<Handle>(fake_handle++);
+  }
 #elif defined(OS_MACOSX)
   typedef base::SharedMemoryHandle Handle;
   // On Mac, the inode number of the backing file is used as an id.
   typedef base::SharedMemoryId Id;
 
   // Returns a default, invalid handle, that is meant to indicate a missing
   // Transport DIB.
   static Handle DefaultHandleValue() { return Handle(); }
+
+  // Returns a value that is ONLY USEFUL FOR TESTS WHERE IT WON'T BE
+  // ACTUALLY USED AS A REAL HANDLE.
+  static Handle GetFakeHandleForTest() {
+    static int fake_handle = 10;
+    return Handle(fake_handle++, false);
+  }
 #elif defined(USE_X11)
   typedef int Handle;  // These two ints are SysV IPC shared memory keys
   typedef int Id;
 
   // Returns a default, invalid handle, that is meant to indicate a missing
   // Transport DIB.
   static Handle DefaultHandleValue() { return -1; }
+
+  // Returns a value that is ONLY USEFUL FOR TESTS WHERE IT WON'T BE
+  // ACTUALLY USED AS A REAL HANDLE.
+  static Handle GetFakeHandleForTest() {
+    static int fake_handle = 10;
+    return fake_handle++;
+  }
 #endif
 
   // Create a new TransportDIB, returning NULL on failure.
   //
   // The size is the minimum size in bytes of the memory backing the transport
   // DIB (we may actually allocate more than that to give us better reuse when
   // cached).
   //
   // The sequence number is used to uniquely identify the transport DIB. It
   // should be unique for all transport DIBs ever created in the same
@@ skipping 46 matching lines @@
   Display* display_;  // connection to the X server
 #endif
   size_t size_;  // length, in bytes
 
   DISALLOW_COPY_AND_ASSIGN(TransportDIB);
 };
 
 class MessageLoop;
 
 #endif  // APP_SURFACE_TRANSPORT_DIB_H_