Delete IsAtLeastOS10_9() and IsAtMostOS10_9()

ui/gfx/mac/io_surface.cc

 // Copyright 2015 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 "ui/gfx/mac/io_surface.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/logging.h"
@@ skipping 146 matching lines @@
   }
 
   IOSurfaceRef surface = IOSurfaceCreate(properties);
 
   // For unknown reasons, triggering this lock on OS X 10.9, on certain GPUs,
   // causes PDFs to render incorrectly. Hopefully this check can be removed once
   // pdfium switches to a Skia backend on Mac.
   // https://crbug.com/594343.
   // IOSurface clearing causes significant performance regression on about half
   // of all devices running Yosemite. https://crbug.com/606850#c22.
-  bool should_clear = !base::mac::IsOS10_9() && !base::mac::IsOS10_10();
+  bool should_clear = base::mac::IsAtLeastOS10_11();
 
   if (should_clear) {
     // Zero-initialize the IOSurface. Calling IOSurfaceLock/IOSurfaceUnlock
     // appears to be sufficient. https://crbug.com/584760#c17
     IOReturn r = IOSurfaceLock(surface, 0, nullptr);
     DCHECK_EQ(kIOReturnSuccess, r);
     r = IOSurfaceUnlock(surface, 0, nullptr);
     DCHECK_EQ(kIOReturnSuccess, r);
   }
 
@@ skipping 11 matching lines @@
     // Note that nullptr is an acceptable input to IOSurfaceSetValue.
     IOSurfaceSetValue(surface, CFSTR("IOSurfaceColorSpace"), color_space_icc);
   }
 
   UMA_HISTOGRAM_TIMES("GPU.IOSurface.CreateTime",
                       base::TimeTicks::Now() - start_time);
   return surface;
 }
 
 }  // namespace gfx