Add ANGLE platform methods for boolean histograms.

ui/gl/angle_platform_impl.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/gl/angle_platform_impl.h"
 
 #include "base/metrics/histogram.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/trace_event/trace_event.h"
 
@@ skipping 77 matching lines @@
   DCHECK_EQ(name, counter->histogram_name());
   counter->Add(sample);
 }
 
 void ANGLEPlatformImpl::histogramSparse(const char* name, int sample) {
   // For sparse histograms, we can use the macro, as it does not incorporate a
   // static.
   UMA_HISTOGRAM_SPARSE_SLOWLY(name, sample);
 }
 
+void ANGLEPlatformImpl::histogramBoolean(const char* name, bool sample) {
+  histogramEnumeration(name, sample ? 1 : 0, 2);
+}
+
 }  // namespace gfx