QUIC - disable QUIC if packet loss rate is bad for a connection.

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 f17542059750002c6fa379e712879675baf45c89..d081f5aa9325d7febb7dcbbdaddc5b91ae0bb157 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -2064,17 +2064,18 @@ Therefore, the affected-histogram name has to have at least one dot in it.
 <histogram name="Autofill.UnmaskPrompt.Events" enum="AutofillUnmaskPromptEvent">
   <owner>waltercacau@chromium.org</owner>
   <summary>
-    Events tracking the usage of the unmasking prompt. This prompt is
-    triggered when a user selects a masked card in a autofill dropdown.
+    Events tracking the usage of the unmasking prompt. This prompt is triggered
+    when a user selects a masked card in a autofill dropdown.
   </summary>
 </histogram>
 
-<histogram name="Autofill.UnmaskPrompt.GetRealPanResult" enum="AutofillGetRealPanResult">
+<histogram name="Autofill.UnmaskPrompt.GetRealPanResult"
+    enum="AutofillGetRealPanResult">
   <owner>waltercacau@chromium.org</owner>
   <summary>
-    Tracks the result of the GetRealPan API call. This API call is triggered
-    by the unmasking prompt when the user types information to verify his
-    ownership of the card being fetched.
+    Tracks the result of the GetRealPan API call. This API call is triggered by
+    the unmasking prompt when the user types information to verify his ownership
+    of the card being fetched.
   </summary>
 </histogram>
 
@@ -19400,6 +19401,16 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Net.QuicSession.HasBadPacketLossRate"
+    enum="BooleanHasBadPacketLossRate">
+  <owner>rtenneti@chromium.org</owner>
+  <summary>
+    Whether the connection has bad packet loss rate or not when cryto handshake
+    is completed. This is logged only after connection has done 5 crypto
+    handshakes.
+  </summary>
+</histogram>
+
 <histogram name="Net.QuicSession.HeadersStream.EarlyFramesReceived">
   <owner>rch@chromium.org</owner>
   <summary>
@@ -45213,6 +45224,11 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <int value="1" label="Hardware accelerated"/>
 </enum>
 
+<enum name="BooleanHasBadPacketLossRate" type="int">
+  <int value="0" label="No high packet loss"/>
+  <int value="1" label="Has high packet loss"/>
+</enum>
+
 <enum name="BooleanHasCrc" type="int">
   <int value="0" label="No CRC"/>
   <int value="1" label="Has CRC"/>
@@ -45403,6 +45419,7 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <int value="1" label="QUIC_STREAM_FACTORY"/>
   <int value="2" label="HTTP_STREAM_FACTORY_IMPL_JOB_ALT"/>
   <int value="3" label="HTTP_STREAM_FACTORY_IMPL_JOB_MAIN"/>
+  <int value="4" label="QUIC_STREAM_FACTORY_BAD_PACKET_LOSS"/>
 </enum>
 
 <enum name="CacheResult" type="int">