Add ANGLE platform methods for boolean histograms.

ui/gl/angle_platform_impl.h

 // 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.
 
 #ifndef UI_GL_ANGLE_PLATFORM_IMPL_H_
 #define UI_GL_ANGLE_PLATFORM_IMPL_H_
 
 // Implements the ANGLE platform interface, for functionality like
 // histograms and trace profiling.
 
@@ skipping 28 matching lines @@
                                 TraceEventHandle handle) override;
   void histogramCustomCounts(const char* name,
                              int sample,
                              int min,
                              int max,
                              int bucket_count) override;
   void histogramEnumeration(const char* name,
                             int sample,
                             int boundary_value) override;
   void histogramSparse(const char* name, int sample) override;
+  void histogramBoolean(const char* name, bool sample) override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ANGLEPlatformImpl);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GL_ANGLE_PLATFORM_IMPL_H_