[Bindings][UMA] Split user metrics for window proxy initialization

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 680022e301e0518e34297b3c331f097240bb6b5a..1cf778c1e5cec001dd08f04a4eb5dde8c873c23d 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -4543,15 +4543,58 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <summary>Records whenever a Blimp tab toggles visibility.</summary>
 </histogram>
 
+<histogram name="Blink.Binding.InitializeMainLocalWindowProxy"
+    units="microseconds">
+  <owner>peria@chromium.org</owner>
+  <summary>
+    Time spent initializing LocalWindowProxy during a page loading in main
+    windows.
+  </summary>
+</histogram>
+
+<histogram name="Blink.Binding.InitializeMainRemoteWindowProxy"
+    units="microseconds">
+  <owner>peria@chromium.org</owner>
+  <summary>
+    Time spent initializing RemoteWindowProxy during a page loading in main
+    frame of OOPIF.
+  </summary>
+</histogram>
+
 <histogram name="Blink.Binding.InitializeMainWindowProxy" units="microseconds">
+  <obsolete>
+    Deprecated as of 03/2017. This metric was split into two metrics depending
+    if it figures time for local window proxies or remote ones.
+  </obsolete>
   <owner>peria@chromium.org</owner>
   <summary>
     Time spent initializing WindowProxy during a page loading in main windows.
   </summary>
 </histogram>
 
+<histogram name="Blink.Binding.InitializeNonMainLocalWindowProxy"
+    units="microseconds">
+  <owner>peria@chromium.org</owner>
+  <summary>
+    Time spent initializing LocalWindowProxy during a page loading in non-main
+    windows, e.g. iframe.
+  </summary>
+</histogram>
+
+<histogram name="Blink.Binding.InitializeNonMainRemoteWindowProxy"
+    units="microseconds">
+  <owner>peria@chromium.org</owner>
+  <summary>
+    Time spent initializing RemoteWindowProxy during a page loading in OOPIF.
+  </summary>
+</histogram>
+
 <histogram name="Blink.Binding.InitializeNonMainWindowProxy"
     units="microseconds">
+  <obsolete>
+    Deprecated as of 03/2017. This metric was split into two metrics depending
+    if it figures time for local window proxies or remote ones.
+  </obsolete>
   <owner>peria@chromium.org</owner>
   <summary>
     Time spent initializing WindowProxy during a page loading in non-main