Add GrabWindowSnapshot method to mac_util class. This code is due to dmaclac...

base/mac_util_unittest.mm

-// Copyright (c) 2008 The Chromium Authors. All rights reserved.
+// Copyright (c) 2008-2009 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.
 
+#import <Cocoa/Cocoa.h>
+#include <vector>
+
 #include "base/mac_util.h"
 
-#include <ApplicationServices/ApplicationServices.h>
-
 #include "base/file_path.h"
+#include "base/scoped_nsobject.h"
+#include "base/scoped_ptr.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/platform_test.h"
 
 typedef PlatformTest MacUtilTest;
 
 TEST_F(MacUtilTest, TestFSRef) {
   FSRef ref;
   std::string path("/System/Library");
 
   ASSERT_TRUE(mac_util::FSRefFromPath(path, &ref));
   EXPECT_EQ(path, mac_util::PathFromFSRef(ref));
 }
 
 TEST_F(MacUtilTest, TestLibraryPath) {
   FilePath library_dir = mac_util::GetUserLibraryPath();
   // Make sure the string isn't empty.
   EXPECT_FALSE(library_dir.value().empty());
 }
+
+TEST_F(MacUtilTest, TestGrabWindowSnapshot) {
+  // Launch a test window so we can take a snapshot.
+  [NSApplication sharedApplication];
+  NSRect frame = NSMakeRect(0, 0, 400, 400);
+  scoped_nsobject<NSWindow> window(
+      [[NSWindow alloc] initWithContentRect:frame
+                                  styleMask:NSBorderlessWindowMask
+                                    backing:NSBackingStoreBuffered
+                                      defer:NO]);
+  [window setBackgroundColor:[NSColor whiteColor]];
+  [window makeKeyAndOrderFront:NSApp];
+
+  scoped_ptr<std::vector<unsigned char> > png_representation(
+      new std::vector<unsigned char>);
+  mac_util::GrabWindowSnapshot(window, png_representation.get());
+
+  // Copy png back into NSData object so we can make sure we grabbed a png.
+  scoped_nsobject<NSData> image_data(
+      [[NSData alloc] initWithBytes:&(*png_representation)[0]
+                             length:png_representation->size()]);
+  NSBitmapImageRep* rep = [NSBitmapImageRep imageRepWithData:image_data.get()];
+  EXPECT_TRUE([rep isKindOfClass:[NSBitmapImageRep class]]);
+  EXPECT_TRUE(CGImageGetWidth([rep CGImage]) == 400);
+  NSColor* color = [rep colorAtX:200 y:200];
+  CGFloat red = 0, green = 0, blue = 0, alpha = 0;
+  [color getRed:&red green:&green blue:&blue alpha:&alpha];
+  EXPECT_GE(red + green + blue, 3.0);
+}