Use a flag to support IndexedDB getAll() optimization.

IndexedDB IDBObjectStore.getAll() has limitations in Chrome that
database file larger than certain amount (>150MB) will cause
browser crash. Use this flag to guard it so that users can choose
to turn on/off this feature for their usage.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=221745579

dist/lovefield.js

@@ -3753,6 +3753,7 @@ lf.Flags = {};
 lf.Flags.MEMORY_ONLY = !1;
 lf.Flags.NATIVE_ES6 = !1;
 lf.Flags.EXCEPTION_URL = "http://google.github.io/lovefield/error_lookup/src/error_lookup.html?c=";
+lf.Flags.IDB_GETALL_OPTIMIZATION = !0;
 lf.structs = {};
 lf.structs.map = {};
 $jscomp.scope.detectUseNative = function() {
@@ -6361,7 +6362,7 @@ lf.backstore.ObjectStore = function(store, deserializeFn) {
 };
 lf.backstore.ObjectStore.prototype.get = function(ids) {
   if (0 == ids.length) {
-    return goog.isDefAndNotNull(this.store_.getAll) ? this.getAllBulk_() : this.getAllWithCursor_();
+    return lf.Flags.IDB_GETALL_OPTIMIZATION && goog.isDefAndNotNull(this.store_.getAll) ? this.getAllBulk_() : this.getAllWithCursor_();
   }
   var promises = ids.map(function(id) {
     return new goog.Promise(function(resolve, reject) {

lib/backstore/object_store.js

@@ -17,6 +17,7 @@
 goog.provide('lf.backstore.ObjectStore');
 
 goog.require('goog.Promise');
+goog.require('lf.Flags');
 goog.require('lf.Table');
 
 
@@ -43,7 +44,8 @@ lf.backstore.ObjectStore = function(store, deserializeFn) {
 /** @override */
 lf.backstore.ObjectStore.prototype.get = function(ids) {
   if (ids.length == 0) {
-    return goog.isDefAndNotNull(this.store_['getAll']) ?
+    return lf.Flags.IDB_GETALL_OPTIMIZATION &&
+        goog.isDefAndNotNull(this.store_['getAll']) ?
         this.getAllBulk_() : this.getAllWithCursor_();
   }
 

lib/flags.js

@@ -41,3 +41,12 @@ lf.Flags.NATIVE_ES6 = false;
 lf.Flags.EXCEPTION_URL =
     'http://google.github.io/lovefield/error_lookup/src/error_lookup.html?c=';
 
+
+/**
+ * Allows IDBObjectStore.getAll optimization.
+ * @define {boolean} When set to true, Lovefield will use IDBObjectStore.getAll
+ * whenever available. This value is suggested to be set to false, see
+ * https://crbug.com/868177 for more details.
+ */
+lf.Flags.IDB_GETALL_OPTIMIZATION = true;
+