Add font failure telemetry

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 e7cd485b1ed98c025f17cd6d3aeb0b77922036b6..c6da03549c6d9bb58b0886f070e9c0266d19b3ea 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -8920,6 +8920,36 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 

[rkaplow, 2016/07/04 14:45:01]

prefer more specific stuff for the unit - something like 'font families', 'font
files', etc.

[Ilya Kulshin, 2016/07/06 17:56:14]

Done.

+<histogram name="DirectWrite.Fonts.Proxy.FamilyCount" units="Count">
+  <owner>kulshin@chromium.org</owner>
+  <summary>
+    The number of font families as seen by the font proxy in the renderer.
+  </summary>
+</histogram>
+
+<histogram name="DirectWrite.Fonts.Proxy.FontProxyError"
+    enum="DirectWriteFontProxyError">
+  <owner>kulshin@chromium.org</owner>
+  <summary>
+    The errors encountered by the DirectWrite font proxy while loading fonts.
+  </summary>
+</histogram>
+
+<histogram name="DirectWrite.Fonts.Proxy.LastResortFontCount" units="Count">
+  <owner>kulshin@chromium.org</owner>
+  <summary>
+    The number of last resort fallback fonts found on the system as seen by the
+    browser.
+  </summary>
+</histogram>
+
+<histogram name="DirectWrite.Fonts.Proxy.LastResortFontFileCount" units="Count">
+  <owner>kulshin@chromium.org</owner>
+  <summary>
+    The number of font files found for a last resort fallback font.
+  </summary>
+</histogram>
+
 <histogram name="DirectWrite.Fonts.Proxy.LoaderType"
     enum="DirectWriteFontLoaderType">
   <owner>kulshin@chromium.org</owner>
@@ -8948,6 +8978,14 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="DirectWrite.Fonts.Proxy.MessageFilterError"
+    enum="DirectWriteMessageFilterError">
+  <owner>kulshin@chromium.org</owner>
+  <summary>
+    Errors, if any, encountered by the DirectWrite font proxy message filter.
+  </summary>
+</histogram>
+
 <histogram name="DisabledExtension.ExtensionWipedStatus" enum="BooleanWiped">
   <obsolete>
     Deprecated 04/2016 as doesn't have data nor owner.
@@ -70340,12 +70378,29 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="2" label="Non-file loader"/>
 </enum>
 
+<enum name="DirectWriteFontProxyError" type="int">
+  <int value="0" label="FindFamily: send failed"/>
+  <int value="1" label="GetFamilyCount: send failed"/>
+  <int value="2" label="CreateEnumeratorFromKey: invalid key"/>
+  <int value="3" label="CreateEnumeratorFromKey: family index out of range"/>
+  <int value="4" label="GetFontFiles: send failed"/>
+  <int value="5" label="FontfileStream: failed to created mapped file"/>
+</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"/>
+  <int value="4" label="Error: failed to create collection"/>
+</enum>
+
+<enum name="DirectWriteMessageFilterError" type="int">
+  <int value="0" label="OnGetFontFiles: GetFont failed"/>
+  <int value="1" label="OnGetFontFiles: AddFilesForFont failed"/>
+  <int value="2" label="OnGetFontFiles: GetFontFamily failed"/>
+  <int value="3" label="InitializeDirectWrite: GetSystemFontCollection failed"/>
+  <int value="4" label="MapCharacters: could not find family"/>
 </enum>
 
 <enum name="DistillableType" type="int">