Revert of Use DiscardableMemoryManager on Android.

base/memory/discardable_memory.h

Index: base/memory/discardable_memory.h
diff --git a/base/memory/discardable_memory.h b/base/memory/discardable_memory.h
index 9189b5eb027901a0e6e22d87853cd928b0c9fb4b..53d8d0e6f7c40b6b5d8d690a46b15158c4b4c0a5 100644
--- a/base/memory/discardable_memory.h
+++ b/base/memory/discardable_memory.h
@@ -17,7 +17,7 @@
 
 enum DiscardableMemoryType {
   DISCARDABLE_MEMORY_TYPE_NONE,
-  DISCARDABLE_MEMORY_TYPE_ASHMEM,
+  DISCARDABLE_MEMORY_TYPE_ANDROID,
   DISCARDABLE_MEMORY_TYPE_MAC,
   DISCARDABLE_MEMORY_TYPE_EMULATED,
   DISCARDABLE_MEMORY_TYPE_MALLOC
@@ -115,6 +115,10 @@
 
   // Testing utility calls.
 
+  // Check whether a purge of all discardable memory in the system is supported.
+  // Use only for testing!
+  static bool PurgeForTestingSupported();
+
   // Purge all discardable memory in the system. This call has global effects
   // across all running processes, so it should only be used for testing!
   static void PurgeForTesting();