Increasing perf swarming job expiration to 4 hours.

BUG=chromium:633253

Review-Url: https://codereview.chromium.org/2348233005
Cr-Commit-Position: refs/heads/master@{#419561}

testing/buildbot/chromium.perf.fyi.json

@@ -29,7 +29,8 @@
               "os": "Windows-10-10586",
               "pool": "Chrome-perf"
             }
-          ]
+          ],
+          "expiration": 14400
         }
       },
       {
@@ -59,7 +60,8 @@
               "os": "Windows-10-10586",
               "pool": "Chrome-perf"
             }
-          ]
+          ],
+          "expiration": 14400
         }
       },
       {
@@ -88,7 +90,8 @@
               "os": "Windows-10-10586",
               "pool": "Chrome-perf"
             }
-          ]
+          ],
+          "expiration": 14400
         }
       },
       {
@@ -118,7 +121,8 @@
               "os": "Windows-10-10586",
               "pool": "Chrome-perf"
             }
-          ]
+          ],
+          "expiration": 14400
         }
       },
       {
@@ -147,7 +151,8 @@
               "os": "Windows-10-10586",
               "pool": "Chrome-perf"
             }
-          ]
+          ],
+          "expiration": 14400
         }
       },
       {
@@ -177,7 +182,8 @@
               "os": "Windows-10-10586",
               "pool": "Chrome-perf"
             }
-          ]
+          ],
+          "expiration": 14400
         }
       },
       {
@@ -206,7 +212,8 @@
               "os": "Windows-10-10586",
               "pool": "Chrome-perf"
             }
-          ]
+          ],
+          "expiration": 14400
         }
       },
       {
@@ -236,7 +243,8 @@
               "os": "Windows-10-10586",
               "pool": "Chrome-perf"
             }
-          ]
+          ],
+          "expiration": 14400
         }
       },
       {
@@ -265,7 +273,8 @@
               "os": "Windows-10-10586",
               "pool": "Chrome-perf"
             }
-          ]
+          ],
+          "expiration": 14400
         }
       },
       {
@@ -295,7 +304,8 @@
               "os": "Windows-10-10586",
               "pool": "Chrome-perf"
             }
-          ]
+          ],
+          "expiration": 14400
         }
       }
     ]

tools/perf/generate_perf_json.py

@@ -305,6 +305,7 @@ def generate_telemetry_test(swarming_dimensions, benchmark_name, browser):
     # Always say this is true regardless of whether the tester
     # supports swarming. It doesn't hurt.
     'can_use_on_swarming_builders': True,
+    'expiration': 14400,
     'dimension_sets': swarming_dimensions
   }