mac: Add tests for reading images from NSPasteboard.

ui/base/clipboard/clipboard_mac.mm

 // Copyright (c) 2012 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.
 
 #include "ui/base/clipboard/clipboard_mac.h"
 
 #import <Cocoa/Cocoa.h>
 #include <stdint.h>
 
 #include <limits>
@@ skipping 280 matching lines @@
   *fragment_end = static_cast<uint32_t>(markup->length());
 }
 
 void ClipboardMac::ReadRTF(ClipboardType type, std::string* result) const {
   DCHECK(CalledOnValidThread());
   DCHECK_EQ(type, CLIPBOARD_TYPE_COPY_PASTE);
 
   return ReadData(GetRtfFormatType(), result);
 }
 
-SkBitmap ClipboardMac::ReadImage(ClipboardType type) const {
+SkBitmap ClipboardMac::ReadImage(ClipboardType type, NSPasteboard* pb) const {
   DCHECK(CalledOnValidThread());
   DCHECK_EQ(type, CLIPBOARD_TYPE_COPY_PASTE);
 
   // If the pasteboard's image data is not to its liking, the guts of NSImage
   // may throw, and that exception will leak. Prevent a crash in that case;
   // a blank image is better.
   base::scoped_nsobject<NSImage> image;
-  NSPasteboard* pb = GetPasteboard();
   @try {
     if ([[pb types] containsObject:NSFilenamesPboardType]) {
       // -[NSImage initWithPasteboard:] gets confused with copies of a single
       // file from the Finder, so extract the path ourselves.
       // http://crbug.com/553686
       NSArray* paths = [pb propertyListForType:NSFilenamesPboardType];
       if ([paths count]) {
         // If N number of files are selected from finder, choose the last one.
         image.reset([[NSImage alloc]
             initWithContentsOfURL:[NSURL fileURLWithPath:[paths lastObject]]]);
       }
     } else {
       if (pb)
         image.reset([[NSImage alloc] initWithPasteboard:pb]);
     }
   } @catch (id exception) {
   }
 
   SkBitmap bitmap;
   if (image.get()) {
     bitmap = skia::NSImageToSkBitmapWithColorSpace(
         image.get(), /*is_opaque=*/ false, base::mac::GetSystemColorSpace());
   }
   return bitmap;
 }
 
+SkBitmap ClipboardMac::ReadImage(ClipboardType type) const {
+  return ReadImage(type, GetPasteboard());
+}
+
 void ClipboardMac::ReadCustomData(ClipboardType clipboard_type,
                                   const base::string16& type,
                                   base::string16* result) const {
   DCHECK(CalledOnValidThread());
   DCHECK_EQ(clipboard_type, CLIPBOARD_TYPE_COPY_PASTE);
 
   NSPasteboard* pb = GetPasteboard();
   if ([[pb types] containsObject:kWebCustomDataPboardType]) {
     NSData* data = [pb dataForType:kWebCustomDataPboardType];
     if ([data length])
@@ skipping 109 matching lines @@
 // Write an extra flavor that signifies WebKit was the last to modify the
 // pasteboard. This flavor has no data.
 void ClipboardMac::WriteWebSmartPaste() {
   NSPasteboard* pb = GetPasteboard();
   NSString* format = GetWebKitSmartPasteFormatType().ToNSString();
   [pb addTypes:[NSArray arrayWithObject:format] owner:nil];
   [pb setData:nil forType:format];
 }
 
 }  // namespace ui