http/tests/cache/disk-cache/disk-cache-validation-back-navigation-policy.html is flaky.

• Component: New Bugs
• Status: NEW ---

[Matt Lewis]

http/tests/cache/disk-cache/disk-cache-validation-back-navigation-policy.html has started to become a flaky failure on macOS WK2 Release according to the flakiness dashboard:

https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=http%2Ftests%2Fcache%2Fdisk-cache%2Fdisk-cache-validation-back-navigation-policy.html

Previously the test was marked for a flaky timeout on Release and A flaky Failure or Timeout for Debug tests in https://bugs.webkit.org/show_bug.cgi?id=149087

Build:
https://build.webkit.org/results/Apple%20Sierra%20Release%20WK2%20(Tests)/r223605%20(5091)/results.html
https://build.webkit.org/builders/Apple%20Sierra%20Release%20WK2%20(Tests)/builds/5091

Diff:

--- /Volumes/Data/slave/sierra-release-tests-wk2/build/layout-test-results/http/tests/cache/disk-cache/disk-cache-validation-back-navigation-policy-expected.txt
+++ /Volumes/Data/slave/sierra-release-tests-wk2/build/layout-test-results/http/tests/cache/disk-cache/disk-cache-validation-back-navigation-policy-actual.txt
@@ -824,10 +824,10 @@
 
 --------Testing loads through memory cache (subresource behavior)--------
 response headers: undefined
-response source: Disk cache
+response source: Network
 
 response headers: {"Cache-control":"max-age=0"}
-response source: Disk cache
+response source: Network
 
 response headers: {"Cache-control":"max-age=100"}
 response source: Memory cache
@@ -842,13 +842,13 @@
 response source: Network
 
 response headers: {"Cache-control":"no-cache"}
-response source: Disk cache
+response source: Network
 
 response headers: {"Cache-control":"max-age=0, no-cache"}
-response source: Disk cache
+response source: Network
 
 response headers: {"Cache-control":"max-age=100, no-cache"}
-response source: Disk cache
+response source: Network
 
 response headers: {"ETag":"match"}
 response source: Memory cache after validation
@@ -905,10 +905,10 @@
 response source: Network
 
 response headers: {"Cache-control":"must-revalidate"}
-response source: Disk cache
+response source: Network
 
 response headers: {"Cache-control":"max-age=0, must-revalidate"}
-response source: Disk cache
+response source: Network
 
 response headers: {"Cache-control":"max-age=100, must-revalidate"}
 response source: Memory cache
@@ -923,13 +923,13 @@
 response source: Network
 
 response headers: {"Cache-control":"no-cache, must-revalidate"}
-response source: Disk cache
+response source: Network
 
 response headers: {"Cache-control":"max-age=0, no-cache, must-revalidate"}
-response source: Disk cache
+response source: Network
 
 response headers: {"Cache-control":"max-age=100, no-cache, must-revalidate"}
-response source: Disk cache
+response source: Network
 
 response headers: {"ETag":"match","Cache-control":"must-revalidate"}
 response source: Memory cache after validation