Add ANGLE platform methods for boolean histograms.

ui/gl/angle_platform_impl.cc

Index: ui/gl/angle_platform_impl.cc
diff --git a/ui/gl/angle_platform_impl.cc b/ui/gl/angle_platform_impl.cc
index 732f0882ac76258c5479f52d343690539c4283b9..80033f8ae3d648a1bb5e6817d6d5e37ef27ac133 100644
--- a/ui/gl/angle_platform_impl.cc
+++ b/ui/gl/angle_platform_impl.cc
@@ -95,4 +95,8 @@ void ANGLEPlatformImpl::histogramSparse(const char* name, int sample) {
   UMA_HISTOGRAM_SPARSE_SLOWLY(name, sample);
 }
 
+void ANGLEPlatformImpl::histogramBoolean(const char* name, bool sample) {
+  UMA_HISTOGRAM_BOOLEAN(name, sample);

[Alexei Svitkine (slow), 2015/05/19 17:32:55]

You have to expand out the macro, like you do for histgramEnumeration - as the
current macro caches the histogram object and won't work if you log two
different histograms.

You can probably just call histogramEnumeration(name, sample ? 1 : 0, 2); here.

[Jamie Madill, 2015/05/19 17:55:33]

Done.

+}
+
 }  // namespace gfx