[Tentaive patch for discussion] Add Purge+Suspend metrics as UMA.

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 c5a7943bf8a0469eeefc4aa4a2450fcefd639175..e0a89a9a828d1894fcaf3a782894c8f7f8873322 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -47523,6 +47523,114 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="PurgeAndSuspend.BlinkGCGrowth" units="KB">
+  <owner>tasak@google.com</owner>
+  <summary>
+    The difference of total allocated object size of BilnkGC allocator between
+    before and after purge and suspend. If the size is increased, the difference
+    is reported as BlinkGCGrowth.
+  </summary>
+</histogram>
+
+<histogram name="PurgeAndSuspend.BlinkGCShrink" units="KB">
+  <owner>tasak@google.com</owner>
+  <summary>
+    The difference of total allocated object size of BilnkGC allocator between
+    before and after purge and suspend. If the size is reduced, the difference
+    is reported as BlinkGCShrink.
+  </summary>
+</histogram>
+
+<histogram name="PurgeAndSuspend.DiscardableGrowth" units="KB">
+  <owner>tasak@google.com</owner>
+  <summary>
+    The difference of discardable memory usage between before and after purge
+    and suspend. If the size is increased, the difference is reported as this
+    UMA, i.e. DiscardableGrowth.
+  </summary>
+</histogram>
+
+<histogram name="PurgeAndSuspend.DiscardableShrink" units="KB">
+  <owner>tasak@google.com</owner>
+  <summary>
+    The difference of discardable memory usage between before and after purge
+    and suspend. If the size is reduced, the difference is reported as this UMA,
+    i.e. DiscardableShrink.
+  </summary>
+</histogram>
+
+<histogram name="PurgeAndSuspend.MallocGrowth" units="KB">
+  <owner>tasak@google.com</owner>
+  <summary>
+    The difference of malloc memory usage between before and after purge and
+    suspend. If the size is increased, the difference is reported as this UMA,
+    i.e. MallocGrowth.
+  </summary>
+</histogram>
+
+<histogram name="PurgeAndSuspend.MallocShrink" units="KB">
+  <owner>tasak@google.com</owner>
+  <summary>
+    The difference of malloc memory usage between before and after purge and
+    suspend. If the size is reduced, the difference is reported as this UMA,
+    i.e. MallocShrink.
+  </summary>
+</histogram>
+
+<histogram name="PurgeAndSuspend.PartitionAllocGrowth" units="KB">
+  <owner>tasak@google.com</owner>
+  <summary>
+    The difference of the total allocated object size of partition alloc between
+    before and after purge and suspend. If the size is increased, the difference
+    is reported as this UMA, i.e. PartitionAllocGrowth.
+  </summary>
+</histogram>
+
+<histogram name="PurgeAndSuspend.PartitionAllocShrink" units="KB">
+  <owner>tasak@google.com</owner>
+  <summary>
+    The difference of the total allocated object size of partition alloc between
+    before and after purge and suspend. If the size is reduced, the difference
+    is reported as this UMA, i.e. PartitionAllocShrink.
+  </summary>
+</histogram>
+
+<histogram name="PurgeAndSuspend.ResidentSizeGrowth" units="KB">
+  <owner>tasak@google.com</owner>
+  <summary>
+    The difference of the resident size between before and after purge and
+    suspend. If the size is increased, the difference is reported as this UMA,
+    i.e. ResidentSizeGrowth.
+  </summary>
+</histogram>
+
+<histogram name="PurgeAndSuspend.ResidentSizeShrink" units="KB">
+  <owner>tasak@google.com</owner>
+  <summary>
+    The difference of the resident size between before and after purge and
+    suspend. If the size is reduced, the difference is reported as this UMA,
+    i.e. ResidentSizeShrink.
+  </summary>
+</histogram>
+
+<histogram name="PurgeAndSuspend.TotalGrowth" units="KB">
+  <owner>tasak@google.com</owner>
+  <summary>
+    The difference of the sum of PartitionAlloc, malloc, discardable, and
+    BlinkGC usage between before and after purge and suspend. If the sum is
+    increased, the difference is reported as this UMA, i.e. TotalGrowth.
+  </summary>
+</histogram>
+
+<histogram name="PurgeAndSuspend.TotalShrink" units="KB">
+  <owner>tasak@google.com</owner>
+  <summary>
+    The difference of the sum of PartitionAlloc, malloc, discardable, and
+    BlinkGC usage between before and after purge and suspend. If the sum is
+    reduced, the difference is reported as this UMA, i.e. TotalShrink.
+  </summary>
+</histogram>
+
 <histogram name="PushMessaging.BackgroundBudget">
   <owner>harkness@chromium.org</owner>
   <summary>