Rewrite clipboard write IPC handling to be easier to understand.

ui/base/clipboard/scoped_clipboard_writer.cc

 // 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.
 
 // This file implements the ScopedClipboardWriter class. Documentation on its
 // purpose can be found in our header. Documentation on the format of the
 // parameters for each clipboard target can be found in clipboard.h.
 
 #include "ui/base/clipboard/scoped_clipboard_writer.h"
 
@@ skipping 68 matching lines @@
   html.append("\">");
   html.append(net::EscapeForHTML(base::UTF16ToUTF8(anchor_text)));
   html.append("</a>");
   WriteHTML(base::UTF8ToUTF16(html), std::string());
 }
 
 void ScopedClipboardWriter::WriteWebSmartPaste() {
   objects_[Clipboard::CBF_WEBKIT] = Clipboard::ObjectMapParams();
 }
 
+void ScopedClipboardWriter::WriteImage(const SkBitmap& bitmap) {
+  if (bitmap.drawsNothing()) {
+    NOTREACHED();
+    return;
+  }
+  bitmap_ = bitmap;
+  // TODO(dcheng): This is slightly less horrible than what we used to do, but
+  // only very slightly less.
+  SkBitmap* bitmap_pointer = &bitmap_;
+  Clipboard::ObjectMapParam packed_pointer;

[jamesr, 2014/09/22 22:38:41]

can you use bit_cast<Clipboard::ObjectMapParam>(&bitmap_) from base/macros.h ?

[dcheng, 2014/09/22 23:06:25]

I don't think I can use bit_cast directly here, because it wouldn't know how to
memcpy into std::vector's internal buffer.

+  for (size_t i = 0; i < sizeof(bitmap_pointer); ++i)

[jamesr, 2014/09/22 22:38:41]

oh god

[dcheng, 2014/09/22 23:06:25]

Yeah... I think that is the only appropriate response to this code. I still
think this is slightly better than the original version where we sent the
ClipboardObjectMap directly over the IPC message and then tried to do all sorts
of checks in the browser side to make sure it looked sane-ish. I've been
thinking about ideas to fix this insanity as well though in a followup patch.

+    packed_pointer.push_back(reinterpret_cast<uint8_t*>(&bitmap_pointer)[i]);
+  Clipboard::ObjectMapParams parameters;
+  parameters.push_back(packed_pointer);
+  objects_[Clipboard::CBF_SMBITMAP] = parameters;
+}
+
 void ScopedClipboardWriter::WritePickledData(
     const Pickle& pickle, const Clipboard::FormatType& format) {
   std::string format_string = format.Serialize();
   Clipboard::ObjectMapParam format_parameter(format_string.begin(),
                                              format_string.end());
   Clipboard::ObjectMapParam data_parameter;
 
   data_parameter.resize(pickle.size());
   memcpy(const_cast<char*>(&data_parameter.front()),
          pickle.data(), pickle.size());
 
   Clipboard::ObjectMapParams parameters;
   parameters.push_back(format_parameter);
   parameters.push_back(data_parameter);
   objects_[Clipboard::CBF_DATA] = parameters;
 }
 
 void ScopedClipboardWriter::Reset() {
   url_text_.clear();
   objects_.clear();
+  bitmap_.reset();
 }
 
 void ScopedClipboardWriter::WriteTextOrURL(const base::string16& text,
                                            bool is_url) {
   std::string utf8_text = base::UTF16ToUTF8(text);
 
   Clipboard::ObjectMapParams parameters;
   parameters.push_back(Clipboard::ObjectMapParam(utf8_text.begin(),
                                                  utf8_text.end()));
   objects_[Clipboard::CBF_TEXT] = parameters;
 
   if (is_url) {
     url_text_ = utf8_text;
   } else {
     url_text_.clear();
   }
 }
 
 }  // namespace ui