Create 'errors' histogram for failures.

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 a13ac096bc81fdfbb714374816b745e6bbe44d3a..ebf6baf2231bd9788ffea0392c37d08c7227de26 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -64,7 +64,9 @@ The complete list of histograms will be:
 
 When 'ordering="prefix"' is present in the histogram_suffixes tag, the suffix
 will be inserted after the first dot separator of the affected-histogram name.
-Therefore, the affected-histogram name has to have at least one dot in it.
+Optionally, ordering can be specified as "prefix,N" where N indicates after
+how many dots the suffix should be inserted (default=1). The affected-histogram
+name has to have at least N dots in it.
 
 Googlers: There are also a small number of private internal histograms found at
 http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
@@ -70520,185 +70522,26 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
-<histogram name="UMA.PersistentAllocator.BrowserMetrics.Allocs" units="bytes">
+<histogram base="true" name="UMA.PersistentAllocator.Allocs" units="bytes">
   <owner>bcwhite@chromium.org</owner>
   <owner>asvitkine@chromium.org</owner>
   <summary>
-    Size, before padding, of objects allocated from persistent memory in the
-    browser process. This is updated with every allocation.
-  </summary>
-</histogram>
-
-<histogram name="UMA.PersistentAllocator.BrowserMetrics.UsedPct" units="%">
-  <owner>bcwhite@chromium.org</owner>
-  <owner>asvitkine@chromium.org</owner>
-  <summary>
-    Percentage of persistent memory segment that has been allocated. This is
-    updated only once per reporting cycle.
-  </summary>
-</histogram>
-
-<histogram name="UMA.PersistentAllocator.FieldTrialAllocator.Allocs"
-    units="bytes">
-  <owner>lawrencewu@chromium.org</owner>
-  <owner>bcwhite@chromium.org</owner>
-  <owner>asvitkine@chromium.org</owner>
-  <summary>
-    Size of objects allocated from persistent memory in the browser process for
-    field trials. Updated on each subprocess launch.
-  </summary>
-</histogram>
-
-<histogram name="UMA.PersistentAllocator.FieldTrialAllocator.UsedPct" units="%">
-  <owner>lawrencewu@chromium.org</owner>
-  <owner>bcwhite@chromium.org</owner>
-  <owner>asvitkine@chromium.org</owner>
-  <summary>
-    Percentage of persistent memory segment that has been allocated. This is
-    updated on each subprocess launch.
-  </summary>
-</histogram>
-
-<histogram name="UMA.PersistentAllocator.GpuMetrics.Allocs" units="bytes">
-  <owner>bcwhite@chromium.org</owner>
-  <owner>asvitkine@chromium.org</owner>
-  <summary>
-    Size, before padding, of objects allocated from persistent memory in a GPU
-    process. This is updated with every allocation.
-  </summary>
-</histogram>
-
-<histogram name="UMA.PersistentAllocator.GpuMetrics.UsedPct" units="%">
-  <owner>bcwhite@chromium.org</owner>
-  <owner>asvitkine@chromium.org</owner>
-  <summary>
-    Percentage of persistent memory segment that has been allocated. This is
-    updated only once per reporting cycle.
-  </summary>
-</histogram>
-
-<histogram name="UMA.PersistentAllocator.PpapiBrokerMetrics.Allocs"
-    units="bytes">
-  <owner>bcwhite@chromium.org</owner>
-  <owner>asvitkine@chromium.org</owner>
-  <summary>
-    Size, before padding, of objects allocated from persistent memory in a
-    &quot;PPAPI broker&quot; process. This is updated with every allocation.
-  </summary>
-</histogram>
-
-<histogram name="UMA.PersistentAllocator.PpapiBrokerMetrics.UsedPct" units="%">
-  <owner>bcwhite@chromium.org</owner>
-  <owner>asvitkine@chromium.org</owner>
-  <summary>
-    Percentage of persistent memory segment that has been allocated. This is
-    updated only once per reporting cycle.
+    Size, before padding, of objects allocated from persistent memory. This is
+    updated with every allocation.
   </summary>
 </histogram>
 
-<histogram name="UMA.PersistentAllocator.PpapiPluginMetrics.Allocs"
-    units="bytes">
+<histogram base="true" name="UMA.PersistentAllocator.Errors"
+    enum="PersistentAllocatorErrors">
   <owner>bcwhite@chromium.org</owner>
   <owner>asvitkine@chromium.org</owner>
   <summary>
-    Size, before padding, of objects allocated from persistent memory in a
-    &quot;PPAPI plugin&quot; process. This is updated with every allocation.
+    Errors detected by the persistent memory allocator. These are set when they
+    occur.
   </summary>
 </histogram>
 
-<histogram name="UMA.PersistentAllocator.PpapiPluginMetrics.UsedPct" units="%">
-  <owner>bcwhite@chromium.org</owner>
-  <owner>asvitkine@chromium.org</owner>
-  <summary>
-    Percentage of persistent memory segment that has been allocated. This is
-    updated only once per reporting cycle.
-  </summary>
-</histogram>
-
-<histogram name="UMA.PersistentAllocator.RendererMetrics.Allocs" units="bytes">
-  <owner>bcwhite@chromium.org</owner>
-  <owner>asvitkine@chromium.org</owner>
-  <summary>
-    Size, before padding, of objects allocated from persistent memory in a
-    renderer process. This is updated with every allocation.
-  </summary>
-</histogram>
-
-<histogram name="UMA.PersistentAllocator.RendererMetrics.UsedPct" units="%">
-  <owner>bcwhite@chromium.org</owner>
-  <owner>asvitkine@chromium.org</owner>
-  <summary>
-    Percentage of persistent memory segment that has been allocated. This is
-    updated only once per reporting cycle.
-  </summary>
-</histogram>
-
-<histogram name="UMA.PersistentAllocator.SandboxHelperMetrics.Allocs"
-    units="bytes">
-  <owner>bcwhite@chromium.org</owner>
-  <owner>asvitkine@chromium.org</owner>
-  <summary>
-    Size, before padding, of objects allocated from persistent memory in a
-    &quot;sandbox helper&quot; process. This is updated with every allocation.
-  </summary>
-</histogram>
-
-<histogram name="UMA.PersistentAllocator.SandboxHelperMetrics.UsedPct"
-    units="%">
-  <owner>bcwhite@chromium.org</owner>
-  <owner>asvitkine@chromium.org</owner>
-  <summary>
-    Percentage of persistent memory segment that has been allocated. This is
-    updated only once per reporting cycle.
-  </summary>
-</histogram>
-
-<histogram name="UMA.PersistentAllocator.SetupMetrics.Allocs" units="bytes">
-  <owner>bcwhite@chromium.org</owner>
-  <owner>asvitkine@chromium.org</owner>
-  <summary>
-    Size, before padding, of objects allocated from persistent memory in a setup
-    process. This is updated with every allocation.
-  </summary>
-</histogram>
-
-<histogram name="UMA.PersistentAllocator.SetupMetrics.UsedPct" units="%">
-  <owner>bcwhite@chromium.org</owner>
-  <owner>asvitkine@chromium.org</owner>
-  <summary>
-    Percentage of persistent memory segment that has been allocated. This is
-    updated only once per reporting cycle.
-  </summary>
-</histogram>
-
-<histogram name="UMA.PersistentAllocator.UtilityMetrics.Allocs" units="bytes">
-  <owner>bcwhite@chromium.org</owner>
-  <owner>asvitkine@chromium.org</owner>
-  <summary>
-    Size, before padding, of objects allocated from persistent memory in a
-    &quot;utility&quot; process. This is updated with every allocation.
-  </summary>
-</histogram>
-
-<histogram name="UMA.PersistentAllocator.UtilityMetrics.UsedPct" units="%">
-  <owner>bcwhite@chromium.org</owner>
-  <owner>asvitkine@chromium.org</owner>
-  <summary>
-    Percentage of persistent memory segment that has been allocated. This is
-    updated only once per reporting cycle.
-  </summary>
-</histogram>
-
-<histogram name="UMA.PersistentAllocator.ZygoteMetrics.Allocs" units="bytes">
-  <owner>bcwhite@chromium.org</owner>
-  <owner>asvitkine@chromium.org</owner>
-  <summary>
-    Size, before padding, of objects allocated from persistent memory in a
-    &quot;zygote&quot; process. This is updated with every allocation.
-  </summary>
-</histogram>
-
-<histogram name="UMA.PersistentAllocator.ZygoteMetrics.UsedPct" units="%">
+<histogram base="true" name="UMA.PersistentAllocator.UsedPct" units="%">
   <owner>bcwhite@chromium.org</owner>
   <owner>asvitkine@chromium.org</owner>
   <summary>
@@ -100938,6 +100781,10 @@ value.
   <int value="9" label="DEPRECATED_XML_PROTO_MISMATCH"/>
 </enum>
 
+<enum name="PersistentAllocatorErrors" type="int">
+  <int value="1" label="Allocator memory is corrupt (set only once)"/>
+</enum>
+
 <enum name="PersistentHistogramsInitResult" type="int">
   <int value="0" label="Local-Memory Success"/>
   <int value="1" label="Local-Memory Failure"/>
@@ -115926,6 +115773,63 @@ value.
   <affected-histogram name="Permissions.Requested.CrossOrigin"/>
 </histogram_suffixes>
 
+<histogram_suffixes name="PersistentMemoryAllocs" separator="."
+    ordering="prefix,2">
+  <suffix name="BrowserMetrics" label="For browser process metrics."/>
+  <suffix name="FieldTrialAllocator" label="For field-trial allocator."/>
+  <suffix name="GpuMetrics" label="For GPU process metrics."/>
+  <suffix name="PpapiBrokerMetrics"
+      label="For &quot;PPAPI broker&quot; process metrics."/>
+  <suffix name="PpapiPluginMetrics"
+      label="For &quot;PPAPI plugin&quot; process metrics."/>
+  <suffix name="RendererMetrics" label="For renderer process metrics."/>
+  <suffix name="SandboxHelperMetrics"
+      label="For &quot;sandbox helper&quot; process metrics."/>
+  <suffix name="SetupMetrics" label="For setup metrics."/>
+  <suffix name="UtilityMetrics"
+      label="For &quot;utility&quot; process metrics."/>
+  <suffix name="ZygoteMetrics" label="For &quot;zygote&quot; process metrics."/>
+  <affected-histogram name="UMA.PersistentAllocator.Allocs"/>
+</histogram_suffixes>
+
+<histogram_suffixes name="PersistentMemoryErrors" separator="."
+    ordering="prefix,2">
+  <suffix name="BrowserMetrics" label="For browser process metrics."/>
+  <suffix name="FieldTrialAllocator" label="For field-trial allocator."/>
+  <suffix name="GpuMetrics" label="For GPU process metrics."/>
+  <suffix name="PpapiBrokerMetrics"
+      label="For &quot;PPAPI broker&quot; process metrics."/>
+  <suffix name="PpapiPluginMetrics"
+      label="For &quot;PPAPI plugin&quot; process metrics."/>
+  <suffix name="RendererMetrics" label="For renderer process metrics."/>
+  <suffix name="SandboxHelperMetrics"
+      label="For &quot;sandbox helper&quot; process metrics."/>
+  <suffix name="SetupMetrics" label="For setup metrics."/>
+  <suffix name="UtilityMetrics"
+      label="For &quot;utility&quot; process metrics."/>
+  <suffix name="ZygoteMetrics" label="For &quot;zygote&quot; process metrics."/>
+  <affected-histogram name="UMA.PersistentAllocator.Errors"/>
+</histogram_suffixes>
+
+<histogram_suffixes name="PersistentMemoryUsedPct" separator="."
+    ordering="prefix,2">
+  <suffix name="BrowserMetrics" label="For browser process metrics."/>
+  <suffix name="FieldTrialAllocator" label="For field-trial allocator."/>
+  <suffix name="GpuMetrics" label="For GPU process metrics."/>
+  <suffix name="PpapiBrokerMetrics"
+      label="For &quot;PPAPI broker&quot; process metrics."/>
+  <suffix name="PpapiPluginMetrics"
+      label="For &quot;PPAPI plugin&quot; process metrics."/>
+  <suffix name="RendererMetrics" label="For renderer process metrics."/>
+  <suffix name="SandboxHelperMetrics"
+      label="For &quot;sandbox helper&quot; process metrics."/>
+  <suffix name="SetupMetrics" label="For setup metrics."/>
+  <suffix name="UtilityMetrics"
+      label="For &quot;utility&quot; process metrics."/>
+  <suffix name="ZygoteMetrics" label="For &quot;zygote&quot; process metrics."/>
+  <affected-histogram name="UMA.PersistentAllocator.UsedPct"/>
+</histogram_suffixes>
+
 <histogram_suffixes name="PhysicalWebDebugActions" separator=".">
   <suffix name="ChromeStart" label="when Chrome first starts up"/>
   <suffix name="LaunchFromDiagnostics"