Create direct write font proxy classes and unit tests.

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index a5ee4099da96217704ef2ffe3876845c0daea055..4782ef2db1b1800cc56c974a4c840ae90871dfc0 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -6963,6 +6963,26 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="DirectWrite.Fonts.Proxy.LoaderType"
+    enum="DirectWriteFontLoaderType">
+  <owner>kulshin@chromium.org</owner>
+  <summary>
+    The codepath that was used to load a font family. This is logged in the
+    browser every time a renderer attempts to load a font family, once per font
+    file.
+  </summary>
+</histogram>
+
+<histogram name="DirectWrite.Fonts.Proxy.LoadFamily"
+    enum="DirectWriteLoadFamilyResult">
+  <owner>kulshin@chromium.org</owner>
+  <summary>
+    The outcome of attempting to load a font family in the renderer (success vs
+    failure and number of families). This is logged in the renderer once per
+    family that is loaded.
+  </summary>
+</histogram>
+
 <histogram name="DisabledExtension.ExtensionWipedStatus" enum="BooleanWiped">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <summary>Whether an extension has been wiped out.</summary>
@@ -56221,6 +56241,21 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="1" label="Failed"/>
 </enum>
 
+<enum name="DirectWriteFontLoaderType" type="int">
+  <int value="0" label="File: system font directory"/>
+  <int value="1" label="File: sandbox whitelisted"/>
+  <int value="2" label="File: outside sandbox whitelist"/>
+  <int value="3" label="Other"/>
+</enum>
+
+<enum name="DirectWriteLoadFamilyResult" type="int">
+  <int value="0" label="Success: single family"/>
+  <int value="1" label="Success: matched from collection"/>
+  <int value="2" label="Error: multiple families"/>
+  <int value="3" label="Error: no families"/>
+  <int value="4" label="Error: failed to create colleciton"/>
+</enum>
+
 <enum name="DistillableType" type="int">
   <int value="0" label="Not distillable"/>
   <int value="1" label="Non-mobile-friendly Distillable"/>