Make WebTestProxy handle printing + compositing mode

content/shell/renderer/test_runner/WebTestProxy.cpp

 // Copyright 2013 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/WebTestProxy.h"
 
 #include <cctype>
 
 #include "base/callback_helpers.h"
 #include "base/debug/trace_event.h"
@@ skipping 481 matching lines @@
   m_compositeAndReadbackCallbacks.front().Run(bitmap);
   m_compositeAndReadbackCallbacks.pop_front();
 }
 
 void WebTestProxyBase::CapturePixelsAsync(
     base::Callback<void(const SkBitmap&)> callback) {
   TRACE_EVENT0("shell", "WebTestProxyBase::CapturePixelsAsync");
 
   DCHECK(webWidget()->isAcceleratedCompositingActive());
   DCHECK(!callback.is_null());
+
+  if (m_testInterfaces->testRunner()->isPrinting()) {
+    // TODO(enne): get rid of stateful canvas().
+    webWidget()->layout();
+    paintPagesWithBoundaries();
+    DrawSelectionRect(canvas());
+    SkBaseDevice* device = skia::GetTopDevice(*canvas());
+    const SkBitmap& bitmap = device->accessBitmap(false);
+    callback.Run(bitmap);

[danakj, 2014/05/09 21:17:21]

do you wanna post-task this to keep it async? otherwise printing tests get
somewhat different call stacks?

[enne (OOO), 2014/05/09 21:25:06]

It's a nice thought, but it seems awkward to do with the canvas() being stored
statefully since something else could clobber it in the meantime.  I could make
a copy of the bitmap and then pass that along with the callback, but that seems
wasteful.

Can you think of an ok way to do this?

[danakj, 2014/05/09 21:37:25]

I figured the test harness shouldn't be doing anything else in the meantime so
it should "just work". If that's not true then things are indeed more awkward
until that happens. Alternatively you could post-task this whole block here to
keep it async until the m_canvas can go?

[enne (OOO), 2014/05/09 22:03:20]

Done.

+    return;
+  }
+
   m_compositeAndReadbackCallbacks.push_back(callback);
   webWidget()->compositeAndReadbackAsync(this);
 }
 
 void WebTestProxyBase::setLogConsoleOutput(bool enabled)
 {
     m_logConsoleOutput = enabled;
 }
 
 void WebTestProxyBase::paintRect(const WebRect& rect)
@@ skipping 800 matching lines @@
 
 void WebTestProxyBase::resetInputMethod()
 {
     // If a composition text exists, then we need to let the browser process
     // to cancel the input method's ongoing composition session.
     if (m_webWidget)
         m_webWidget->confirmComposition();
 }
 
 }  // namespace content