Wrap large IndexedDB values into Blobs before writing to LevelDB.

third_party/WebKit/LayoutTests/external/wpt/IndexedDB/support-promises.js

 'use strict';
 
 // Returns an IndexedDB database name that is unique to the test case.
 function databaseName(testCase) {
   return 'db' + self.location.pathname + '-' + testCase.name;
 }
 
 // Creates an EventWatcher covering all the events that can be issued by
 // IndexedDB requests and transactions.
 function requestWatcher(testCase, request) {
@@ skipping 252 matching lines @@
 // is using it incorrectly.
 function checkTitleIndexContents(testCase, index, errorMessage) {
   const request = index.get(BOOKS_RECORD_DATA[2].title);
   const eventWatcher = requestWatcher(testCase, request);
   return eventWatcher.wait_for('success').then(() => {
     const result = request.result;
     assert_equals(result.isbn, BOOKS_RECORD_DATA[2].isbn, errorMessage);
     assert_equals(result.author, BOOKS_RECORD_DATA[2].author, errorMessage);
   });
 }
+
+// Returns an Uint8Array with pseudorandom data.
+//
+// The PRNG should be sufficient to defeat compression schemes, but it is not
+// cryptographically strong.
+function largeValue(size, seed) {
+  const buffer = new Uint8Array(size);
+
+  // 32-bit xorshift - the seed can't be zero
+  let state = 1000 + seed;
+
+  for (let i = 0; i < size; ++i) {
+    state ^= state << 13;
+    state ^= state >> 17;
+    state ^= state << 5;
+    buffer[i] = state & 0xff;
+  }
+
+  return buffer;
+}