Handle malformed built-in PluginFinder data.

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 49c3bfb48f344170ba5a69fda2b1a1748b6886ce..1993bcad7b301e5d8a94eef894129270105cd252 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -28462,6 +28462,12 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="PluginFinder.BuiltInPluginList.ErrorCode"
+    enum="JSONParseError">
+  <owner>bauerb@chromium.org</owner>
+  <summary>Error codes when parsing the built-in plugin list.</summary>

[Alexei Svitkine (slow), 2015/04/20 17:15:10]

Mention when it's logged.

[Bernhard Bauer, 2015/04/21 16:34:11]

Done.

+</histogram>
+
 <histogram name="Power.BacklightLevelOnAC" units="%">
   <owner>derat@chromium.org</owner>
   <summary>
@@ -53709,6 +53715,19 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <int value="4" label="GetMediaDevices"/>
 </enum>
 
+<enum name="JSONParseError" type="int">
+  <int value="0" label="NoError"/>
+  <int value="1" label="InvalidEscape"/>
+  <int value="2" label="SyntaxError"/>
+  <int value="3" label="UnexpectedToken"/>
+  <int value="4" label="TrailingComma"/>
+  <int value="5" label="TooMuchNesting"/>
+  <int value="6" label="UnexpectedDataAfterRoot"/>
+  <int value="7" label="UnsupportedEncoding"/>
+  <int value="8" label="UnquotedDictionaryKey"/>
+  <int value="9" label="SchemaError"/>
+</enum>
+
 <enum name="KeyboardControlEvent" type="int">
   <int value="0" label="Keyboard was shown."/>
   <int value="1" label="Keyboard was automatically hidden."/>