Be robust to printing too large pages in tests

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/callback_helpers.h"
 #include "base/debug/trace_event.h"
@@ skipping 460 matching lines @@
 
   blink::WebSize page_size_in_pixels = web_widget_->size();
   blink::WebFrame* web_frame = GetWebView()->mainFrame();
 
   int page_count = web_frame->printBegin(page_size_in_pixels);
   int totalHeight = page_count * (page_size_in_pixels.height + 1) - 1;
 
   bool is_opaque = false;
   skia::RefPtr<SkCanvas> canvas(skia::AdoptRef(skia::TryCreateBitmapCanvas(
       page_size_in_pixels.width, totalHeight, is_opaque)));
-  if (canvas)
-    web_frame->printPagesWithBoundaries(canvas.get(), page_size_in_pixels);
+  if (!canvas) {
+    callback.Run(SkBitmap());
+    return;
+  }
+  web_frame->printPagesWithBoundaries(canvas.get(), page_size_in_pixels);
   web_frame->printEnd();
 
   DrawSelectionRect(canvas.get());
   SkBaseDevice* device = skia::GetTopDevice(*canvas);
   const SkBitmap& bitmap = device->accessBitmap(false);
   callback.Run(bitmap);
 }
 
 void WebTestProxyBase::CapturePixelsAsync(
     const base::Callback<void(const SkBitmap&)>& callback) {
@@ skipping 746 matching lines @@
   if (!push_client_.get())
     push_client_.reset(new MockWebPushClient);
   return push_client_.get();
 }
 
 blink::WebPushClient* WebTestProxyBase::GetWebPushClient() {
   return GetPushClientMock();
 }
 
 }  // namespace content