Add UMA to track the duration of CheckFrambufferValid

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 03dd7c2f1dd5ec705ea91584b924fbe6c3584b63..d6b8f99e8a8a7ee2802690fa0309e0f327bb3051 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -19294,6 +19294,13 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="GPU.CheckFramebufferValidDuration" units="ms">
+  <owner>ericrk@chromium.org</owner>
+  <summary>
+    The amount of time spent in GLES2DecoderImpl::CheckFramebufferValid.
+  </summary>
+</histogram>
+
 <histogram name="GPU.CollectContextGraphicsInfo" units="microseconds">
   <owner>vmiura@chromium.org</owner>
   <summary>
@@ -19328,6 +19335,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="GPU.DestroyProgramManagerPrograms.Elapsed" units="ms">
+  <obsolete>
+    Deprecated 11/2016.
+  </obsolete>
   <owner>ericrk@chromium.org</owner>
   <summary>
     The amount of time spent destroying programs during ProgramManager::Destroy.
@@ -19335,6 +19345,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="GPU.DestroyProgramManagerPrograms.Programs" units="programs">
+  <obsolete>
+    Deprecated 11/2016.
+  </obsolete>
   <owner>ericrk@chromium.org</owner>
   <summary>
     The number of progams destroyed during ProgramManager::Destroy.
@@ -19343,6 +19356,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 
 <histogram name="GPU.DestroyProgramManagerPrograms.ProgramsPerMs"
     units="programs per ms">
+  <obsolete>
+    Deprecated 11/2016.
+  </obsolete>
   <owner>ericrk@chromium.org</owner>
   <summary>
     The number of programs destroyed per millisecond during