Revert of Memory improvements to render_pdfs; better DM pool size defaults

src/lazy/SkDiscardableMemoryPool.h

Index: src/lazy/SkDiscardableMemoryPool.h
diff --git a/src/lazy/SkDiscardableMemoryPool.h b/src/lazy/SkDiscardableMemoryPool.h
index 57a14db0dd659957ed49b872501b66c53901691c..d141507004151360931df09b8622862dc480962b 100644
--- a/src/lazy/SkDiscardableMemoryPool.h
+++ b/src/lazy/SkDiscardableMemoryPool.h
@@ -62,14 +62,7 @@
 SkDiscardableMemoryPool* SkGetGlobalDiscardableMemoryPool();
 
 #if !defined(SK_DEFAULT_GLOBAL_DISCARDABLE_MEMORY_POOL_SIZE)
-    #if defined(SK_DEFAULT_RESOURCE_CACHE_MB_LIMIT) && \
-            SK_DEFAULT_RESOURCE_CACHE_MB_LIMIT > 0
-        #define SK_DEFAULT_GLOBAL_DISCARDABLE_MEMORY_POOL_SIZE \
-                (SK_DEFAULT_RESOURCE_CACHE_MB_LIMIT * 1024 * 1024)
-    #else
-        #define SK_DEFAULT_GLOBAL_DISCARDABLE_MEMORY_POOL_SIZE \
-                (128 * 1024 * 1024)
-    #endif
+#define SK_DEFAULT_GLOBAL_DISCARDABLE_MEMORY_POOL_SIZE (128 * 1024 * 1024)
 #endif
 
 #endif  // SkDiscardableMemoryPool_DEFINED