Accumulate FileSystemUsageCache updates to improve write performance.

This change reduces the number of usage cache update on appending data to a file, and improves the write performance from 75.72 MB/s (σ = 23.255) to 229.238 MB/s (σ = 31.442) on a benchmark.

https://www.googledrive.com/host/0B0EZi1x_1MtFSnNRZy1nalVNdlk/append-write.html

BUG=166158

Review URL: https://codereview.chromium.org/11639037

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@175474 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 2 insertions, 0 deletions

diff --git a/webkit/fileapi/obfuscated_file_util_unittest.cc b/webkit/fileapi/obfuscated_file_util_unittest.cc
index 349ee1c..c0d3e4e 100644
--- a/webkit/fileapi/obfuscated_file_util_unittest.cc
+++ b/webkit/fileapi/obfuscated_file_util_unittest.cc
@@ -229,6 +229,7 @@ class ObfuscatedFileUtilTest : public testing::Test {
   }
 
   int64 SizeInUsageFile() {
+    MessageLoop::current()->RunUntilIdle();
     return FileSystemUsageCache::GetUsage(test_helper_.GetUsageCachePath());
   }
 
@@ -353,6 +354,7 @@ class ObfuscatedFileUtilTest : public testing::Test {
           expected_usage_(expected_usage) {}
 
     ~UsageVerifyHelper() {
+      MessageLoop::current()->RunUntilIdle();
       Check();
     }