Add test_runner hook to dump drag image.

content/shell/renderer/test_runner/web_test_proxy.cc

 // Copyright 2014 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 "content/shell/renderer/test_runner/web_test_proxy.h"
 
 #include <cctype>
 
+#include "base/base64.h"
 #include "base/callback_helpers.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/trace_event/trace_event.h"
 #include "content/public/common/content_switches.h"
 #include "content/shell/renderer/test_runner/accessibility_controller.h"
 #include "content/shell/renderer/test_runner/event_sender.h"
@@ skipping 780 matching lines @@
 
     delegate_->PrintMessage(message + "\n");
   }
 }
 
 void WebTestProxyBase::StartDragging(blink::WebLocalFrame* frame,
                                      const blink::WebDragData& data,
                                      blink::WebDragOperationsMask mask,
                                      const blink::WebImage& image,
                                      const blink::WebPoint& point) {
+  if (test_interfaces_->GetTestRunner()->shouldDumpDragImage()) {
+    const SkBitmap bitmap = image.getSkBitmap();
+    SkAutoLockPixels lock(bitmap);
+    std::string encoded;
+    base::Base64Encode(base::StringPiece(static_cast<char*>(bitmap.getPixels()),

[jackhou1, 2015/02/10 01:54:20]

Is there a better way to represent the image? This is sufficient for the test,
but there's no way to view the output as an image, and the expectations would
need updating if the pixel format changed.

[Justin Novosad, 2015/02/10 22:37:48]

Yeah this is not ideal. It would be much better to find a way to inject the drag
image into the test's pixel results.  Are your tests going to be outputting
multiple images, or always just one?

[jackhou1, 2015/02/11 00:08:24]

Just one. And I imagine that would be fine for any future tests of DragImage.

I'll look into dumping the image in place of pixel results. Let me know if you
have any suggestions.

+                                         bitmap.getSize()),
+                       &encoded);
+    delegate_->PrintMessage(std::string("DragImage: ") + encoded + "\n");
+  }
   // When running a test, we need to fake a drag drop operation otherwise
   // Windows waits for real mouse events to know when the drag is over.
   test_interfaces_->GetEventSender()->DoDragDrop(data, mask);
 }
 
 // The output from these methods in layout test mode should match that
 // expected by the layout tests. See EditingDelegate.m in DumpRenderTree.
 
 void WebTestProxyBase::DidChangeSelection(bool is_empty_callback) {
   if (test_interfaces_->GetTestRunner()->shouldDumpEditingCallbacks())
@@ skipping 494 matching lines @@
   // to cancel the input method's ongoing composition session.
   if (web_widget_)
     web_widget_->confirmComposition();
 }
 
 blink::WebString WebTestProxyBase::acceptLanguages() {
   return blink::WebString::fromUTF8(accept_languages_);
 }
 
 }  // namespace content