Make page_cycler.py fully measure memory for each page.

tools/telemetry/telemetry/core/platform/mac_platform_backend.py

Index: tools/telemetry/telemetry/core/platform/mac_platform_backend.py
diff --git a/tools/telemetry/telemetry/core/platform/mac_platform_backend.py b/tools/telemetry/telemetry/core/platform/mac_platform_backend.py
index ced415104273e486e38c0abb05dae576fa9d2aa5..edd54b1a778cecfad3734513ab51b042ca4198a1 100644
--- a/tools/telemetry/telemetry/core/platform/mac_platform_backend.py
+++ b/tools/telemetry/telemetry/core/platform/mac_platform_backend.py
@@ -85,6 +85,10 @@ class MacPlatformBackend(posix_platform_backend.PosixPlatformBackend):
         return pages_active * resource.getpagesize() / 1024
     return 0
 
+  def PurgeUnpinnedMemory(self):
+    # TODO(pliard): Implement this.
+    pass
+
   def GetMemoryStats(self, pid):
     rss_vsz = self._GetPsOutput(['rss', 'vsz'], pid)
     if rss_vsz: