Use DiscardableMemoryManager on Android.

base/memory/discardable_memory_linux.cc

Index: base/memory/discardable_memory_linux.cc
diff --git a/base/memory/discardable_memory_linux.cc b/base/memory/discardable_memory_linux.cc
index e44b7c20ce0020fa1ba36bb0259e119488f1fe6c..fbd496d6cd4ed2523cd9e19d1dda51d20f37d128 100644
--- a/base/memory/discardable_memory_linux.cc
+++ b/base/memory/discardable_memory_linux.cc
@@ -35,7 +35,7 @@ scoped_ptr<DiscardableMemory> DiscardableMemory::CreateLockedMemoryWithType(
     DiscardableMemoryType type, size_t size) {
   switch (type) {
     case DISCARDABLE_MEMORY_TYPE_NONE:
-    case DISCARDABLE_MEMORY_TYPE_ANDROID:
+    case DISCARDABLE_MEMORY_TYPE_ASHMEM:
     case DISCARDABLE_MEMORY_TYPE_MAC:
       return scoped_ptr<DiscardableMemory>();
     case DISCARDABLE_MEMORY_TYPE_EMULATED: {
@@ -61,11 +61,6 @@ scoped_ptr<DiscardableMemory> DiscardableMemory::CreateLockedMemoryWithType(
 }
 
 // static
-bool DiscardableMemory::PurgeForTestingSupported() {
-  return true;
-}
-
-// static
 void DiscardableMemory::PurgeForTesting() {
   internal::DiscardableMemoryEmulated::PurgeForTesting();
 }