Add PurgeMemory() method for ChildMemoryCoordinator.mojom

content/common/child_memory_coordinator.mojom

Index: content/common/child_memory_coordinator.mojom
diff --git a/content/common/child_memory_coordinator.mojom b/content/common/child_memory_coordinator.mojom
index 0a20b7fbd3fce8589a4d74b99cfa8c83f3bf40ba..72a463f71f2942d2961ae1f0db9430707b42a5bd 100644
--- a/content/common/child_memory_coordinator.mojom
+++ b/content/common/child_memory_coordinator.mojom
@@ -20,4 +20,7 @@ interface ChildMemoryCoordinator {
   // Called when the central memory coodinator changes the state for child
   // processes.
   OnStateChange(MemoryState state);
+
+  // Requests purging memory.

[dcheng, 2017/02/14 07:48:18]

Nit: I'd suggest rewording this comment to include examples of things child
processes should do in response to this callback, e.g.:

Requests the child process to purge memory (e.g. by dropping caches that can be
easily rebuilt).

[bashi, 2017/02/14 08:02:36]

Done.

+  PurgeMemory();
 };