Printing: Fix undefined behavior for near 0 scaling

components/printing/renderer/print_web_view_helper.h

 // 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.
 
 #ifndef COMPONENTS_PRINTING_RENDERER_PRINT_WEB_VIEW_HELPER_H_
 #define COMPONENTS_PRINTING_RENDERER_PRINT_WEB_VIEW_HELPER_H_
 
 #include <memory>
 #include <vector>
 
@@ skipping 33 matching lines @@
 }
 
 namespace blink {
 class WebFrame;
 class WebLocalFrame;
 class WebView;
 }
 
 namespace printing {
 
+constexpr double kEpsilon = .01f;

[Lei Zhang, 2016/10/29 00:59:27]

Mmm, this adds printing::kEpsilon. Can we declare it within PrintWebViewHelper?
i.e. static constexpr double kEpsilon = 0.01f; around line 115.

[rbpotter, 2016/10/29 01:09:38]

Done.

 struct PageSizeMargins;
 class PrepareFrameAndViewForPrint;
 
 // Stores reference to frame using WebVew and unique name.
 // Workaround to modal dialog issue on Linux. crbug.com/236147.
 // If WebFrame someday supports WeakPtr, we should use it here.
 class FrameReference {
  public:
   explicit FrameReference(blink::WebLocalFrame* frame);
   FrameReference();
@@ skipping 462 matching lines @@
   base::Closure on_stop_loading_closure_;
 
   base::WeakPtrFactory<PrintWebViewHelper> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PrintWebViewHelper);
 };
 
 }  // namespace printing
 
 #endif  // COMPONENTS_PRINTING_RENDERER_PRINT_WEB_VIEW_HELPER_H_