Fix missing null check in Clipboard::ReadImage.

ui/base/clipboard/clipboard_win.cc

 // Copyright (c) 2011 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.
 
 // Many of these functions are based on those found in
 // webkit/port/platform/PasteboardWin.cpp
 
 #include "ui/base/clipboard/clipboard.h"
 
 #include <shlobj.h>
@@ skipping 334 matching lines @@
     return;
   }
 
   const FORMATETC* textFormat = ClipboardUtil::GetPlainTextFormat();
   const FORMATETC* htmlFormat = ClipboardUtil::GetHtmlFormat();
   types->clear();
   if (::IsClipboardFormatAvailable(textFormat->cfFormat))
     types->push_back(UTF8ToUTF16(kMimeTypeText));
   if (::IsClipboardFormatAvailable(htmlFormat->cfFormat))
     types->push_back(UTF8ToUTF16(kMimeTypeHTML));
-  if (::IsClipboardFormatAvailable(CF_BITMAP))
+  if (::IsClipboardFormatAvailable(CF_DIB))
     types->push_back(UTF8ToUTF16(kMimeTypePNG));
   *contains_filenames = false;
 }
 
 void Clipboard::ReadText(Clipboard::Buffer buffer, string16* result) const {
   DCHECK_EQ(buffer, BUFFER_STANDARD);
   if (!result) {
     NOTREACHED();
     return;
   }
@@ skipping 69 matching lines @@
 
   // Acquire the clipboard.
   ScopedClipboard clipboard;
   if (!clipboard.Acquire(GetClipboardWindow()))
     return SkBitmap();
 
   // We use a DIB rather than a DDB here since ::GetObject() with the
   // HBITMAP returned from ::GetClipboardData(CF_BITMAP) always reports a color
   // depth of 32bpp.
   BITMAPINFO* bitmap = static_cast<BITMAPINFO*>(::GetClipboardData(CF_DIB));
+  if (!bitmap)
+    return SkBitmap();
   int color_table_length = 0;
   switch (bitmap->bmiHeader.biBitCount) {
     case 1:
     case 4:
     case 8:
       color_table_length = bitmap->bmiHeader.biClrUsed
           ? bitmap->bmiHeader.biClrUsed
           : 1 << bitmap->bmiHeader.biBitCount;
       break;
     case 16:
@@ skipping 231 matching lines @@
     clipboard_owner_ = ::CreateWindow(L"ClipboardOwnerWindowClass",
                                       L"ClipboardOwnerWindow",
                                       0, 0, 0, 0, 0,
                                       HWND_MESSAGE,
                                       0, 0, 0);
   }
   return clipboard_owner_;
 }
 
 }  // namespace ui