Only record fallback metrics on successful requests.

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 9e22d423d4ec709dd49328e60dcd9f1ee40c0961..47fd27fc4bb1b6c1b06aa8e22e6a882f0464cfb4 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -17803,6 +17803,9 @@ Therefore, the affected-histogram name has to have at least one dot in it.
 
 <histogram name="Net.ConnectionUsedSSLDeprecatedCipherFallback"
     enum="BooleanDeprecatedCiphers">
+  <obsolete>
+    Replaced with Net.ConnectionUsedSSLDeprecatedCipherFallback2 in Chrome 44.
+  </obsolete>
   <owner>davidben@chromium.org</owner>
   <summary>
     True if an HTTPS connection was made using the deprecated cipher suite
@@ -17810,6 +17813,15 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Net.ConnectionUsedSSLDeprecatedCipherFallback2"
+    enum="BooleanDeprecatedCiphers">
+  <owner>davidben@chromium.org</owner>
+  <summary>
+    For each successful HTTPS request, whether it used the deprecated cipher
+    suite fallback.
+  </summary>
+</histogram>
+
 <histogram name="Net.ConnectionUsedSSLv3Fallback">
   <obsolete>
     Replaced by Net.ConnectionUsedSSLVersionFallback in Chrome 21.
@@ -17822,6 +17834,9 @@ Therefore, the affected-histogram name has to have at least one dot in it.
 
 <histogram name="Net.ConnectionUsedSSLVersionFallback"
     enum="FallbackSSLVersion">
+  <obsolete>
+    Replaced with Net.ConnectionUsedSSLVersionFallback2 in Chrome 44.
+  </obsolete>
   <owner>agl@chromium.org</owner>
   <summary>
     Nonzero if the HTTP request was to a server which requires SSL version
@@ -17829,6 +17844,15 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Net.ConnectionUsedSSLVersionFallback2"
+    enum="FallbackSSLVersion">
+  <owner>davidben@chromium.org</owner>
+  <summary>
+    For each successful HTTPS request, whether it used the SSL version fallback.
+    The value indicates the SSL version the request fell back on
+  </summary>
+</histogram>
+
 <histogram name="net.CookieBackingStoreUpdateResults"
     enum="BackingStoreResults">
   <obsolete>
@@ -18770,6 +18794,9 @@ Therefore, the affected-histogram name has to have at least one dot in it.
 
 <histogram name="Net.GoogleConnectionUsedSSLVersionFallback"
     enum="FallbackSSLVersion">
+  <obsolete>
+    Replaced with Net.GoogleConnectionUsedSSLVersionFallback2 in Chrome 44.
+  </obsolete>
   <owner>agl@chromium.org</owner>
   <summary>
     Nonzero if the HTTP request was to a Google server which required SSL
@@ -18779,6 +18806,17 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Net.GoogleConnectionUsedSSLVersionFallback2"
+    enum="FallbackSSLVersion">
+  <owner>davidben@chromium.org</owner>
+  <summary>
+    For each successful HTTPS request to a Google server, whether it used the
+    SSL version fallback. The value indicates the SSL version the request fell
+    back on. Since Google servers support TLS 1.2, any fallback is an indication
+    of network middleware problems.
+  </summary>
+</histogram>
+
 <histogram name="Net.GzipEncodingFixupResult" enum="GzipEncodingFixupResult">
   <obsolete>
     Removed around 2015/03/18. The code which implemented Gzip encoding fixup