IndexedDB: Limit the size of a leveldb write buffer to minimize disk space.

third_party/leveldatabase/env_chromium.h

Index: third_party/leveldatabase/env_chromium.h
diff --git a/third_party/leveldatabase/env_chromium.h b/third_party/leveldatabase/env_chromium.h
index 51f28666c34479125e9f150877a2dac6b23ed983..6cc5d45ee330bf05878b975e0994177fb87f4b88 100644
--- a/third_party/leveldatabase/env_chromium.h
+++ b/third_party/leveldatabase/env_chromium.h
@@ -97,6 +97,15 @@ int GetNumCorruptionCodes();
 std::string GetCorruptionMessage(const leveldb::Status& status);
 bool IndicatesDiskFull(const leveldb::Status& status);
 
+// Determine the appropriate leveldb write buffer size to use. The default size
+// (4MB) may result in a log file too large to be compacted given the available
+// storage space. This function will return smaller values for smaller disks,
+// and the default leveldb value for larger disks.
+//
+// |path| is the path to any file or directory on the partition on which the
+// leveldb will be created/opened.
+size_t WriteBufferSize(const base::FilePath& path);
+
 class UMALogger {
  public:
   virtual void RecordErrorAt(MethodID method) const = 0;