Count presence of viewport tag as mobile-friendly

third_party/WebKit/Source/core/frame/VisualViewport.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 758 matching lines @@
 }
 
 bool VisualViewport::shouldDisableDesktopWorkarounds() const {
   if (!mainFrame() || !mainFrame()->view())
     return false;
 
   if (!mainFrame()->settings()->viewportEnabled())
     return false;
 
   // A document is considered adapted to small screen UAs if one of these holds:
-  // 1. The author specified viewport has a constrained width that is equal to
-  //    the initial viewport width.
+  // 1. The author specified viewport has a constrained width that is smaller or
+  //    equal to the initial viewport width.
   // 2. The author has disabled viewport zoom.
   const PageScaleConstraints& constraints =
       frameHost().pageScaleConstraintsSet().pageDefinedConstraints();
 
-  return mainFrame()->view()->layoutSize().width() == m_size.width() ||
+  return mainFrame()->view()->layoutSize().width() <= m_size.width() ||

[aelias_OOO_until_Jul13, 2016/10/24 21:48:59]

Hmm, I think we should decouple this from the details of resolved viewport width
and screen size entirely.

Could you delete this logic entirely and merge this detection with
matchesHeuristicsForGpuRasterization?  That checks if the
ViewportDescription.isSpecifiedByAuthor.  Might make sense to rename some of the
GPU-raster-related names to m_viewportSpecifiedByAuthor as well and generalize
it to this use.

(The other uses of shouldDisableDesktopWorkarounds are for tap disambiguation
stuff and double-tap zoom stuff, both of which should also be OK with switching
to *any* viewport tag.)

[wychen, 2016/10/24 23:18:52]

Done.

          (constraints.minimumScale == constraints.maximumScale &&
           constraints.minimumScale != -1);
 }
 
 CompositorAnimationTimeline* VisualViewport::compositorAnimationTimeline()
     const {
   ScrollingCoordinator* c = frameHost().page().scrollingCoordinator();
   return c ? c->compositorAnimationTimeline() : nullptr;
 }
 
@@ skipping 27 matching lines @@
   } else if (graphicsLayer == m_rootTransformLayer.get()) {
     name = "Root Transform Layer";
   } else {
     ASSERT_NOT_REACHED();
   }
 
   return name;
 }
 
 }  // namespace blink