SharedPageState ensures specified page cache temperature.

telemetry/telemetry/page/cache_temperature.py

Index: telemetry/telemetry/page/cache_temperature.py
diff --git a/telemetry/telemetry/page/cache_temperature.py b/telemetry/telemetry/page/cache_temperature.py
index 01bae7c86cb3f946c3ce5de8ae485c61d70e3690..004896ee5c61fbe1ac56b8f9b75698b23dd799b6 100644
--- a/telemetry/telemetry/page/cache_temperature.py
+++ b/telemetry/telemetry/page/cache_temperature.py
@@ -10,6 +10,9 @@ See design doc for details:
 https://docs.google.com/document/u/1/d/12D7tkhZi887g9d0U2askU9JypU_wYiEI7Lw0bfwxUgA
 """
 
+import logging
+from telemetry.core import util
+
 # Default Cache Temperature. The page doesn't care which browser cache state
 # it is run on.
 ANY = 'any'
@@ -19,3 +22,35 @@ PCV1_COLD = 'pcv1-cold'
 # Emulates PageCycler V1 warm runs. Ensures that the page was visited at least
 # once just before the run.
 PCV1_WARM = 'pcv1-warm'
+
+
+def EnsurePageCacheTemperature(page, browser, previous_page=None):
+  temperature = page.cache_temperature
+  logging.info('PageCacheTemperature: %s', temperature)
+
+  if temperature == ANY:
+    return
+  elif temperature == PCV1_COLD:
+    any_valid_tab = browser.tabs[0]
+    any_valid_tab.ClearCache(force=True)
+  elif temperature == PCV1_WARM:
+    if (previous_page is not None and
+        previous_page.url == page.url and
+        (previous_page.cache_temperature == PCV1_COLD or
+            previous_page.cache_temperature == PCV1_WARM)):
+      return
+
+    tab = browser.tabs[0]
+    tab.ExecuteJavaScript(
+        """console.time('telemetry.internal.warmCache.start');""")
+    tab.ExecuteJavaScript(
+        """console.timeEnd('telemetry.internal.warmCache.start');""")
+    tab.Navigate(page.url)
+    util.WaitFor(tab.HasReachedQuiescence, 60)
+    tab.WaitForDocumentReadyStateToBeComplete()
+    tab.Navigate("about:blank")
+    tab.WaitForDocumentReadyStateToBeComplete()
+    tab.ExecuteJavaScript(
+        """console.time('telemetry.internal.warmCache.end');""")
+    tab.ExecuteJavaScript(
+        """console.timeEnd('telemetry.internal.warmCache.end');""")