IDB: Implement SQLite backing store 'get' support

IDB: Implement SQLite backing store 'get' support
https://bugs.webkit.org/show_bug.cgi?id=127502

Reviewed by Tim Horton.

Source/WebCore:

Get a KeyRange from a KeyRangeData:
* Modules/indexeddb/IDBKeyRangeData.cpp:
(WebCore::IDBKeyRangeData::maybeCreateIDBKeyRange):
* Modules/indexeddb/IDBKeyRangeData.h:

Add collation function support to SQLiteDatabase:
* platform/sql/SQLiteDatabase.cpp:
(WebCore::destroyCollationFunction):
(WebCore::callCollationFunction):
(WebCore::SQLiteDatabase::setCollationFunction):
(WebCore::SQLiteDatabase::removeCollationFunction):
* platform/sql/SQLiteDatabase.h:

* WebCore.exp.in:

Source/WebKit2:

This makes get of a single IDBKey work, and lays the groundwork for getting an IDBKeyRange.

* DatabaseProcess/IndexedDB/UniqueIDBDatabase.cpp:
(WebKit::UniqueIDBDatabase::getRecordFromBackingStore):
* DatabaseProcess/IndexedDB/UniqueIDBDatabaseBackingStore.h:

* DatabaseProcess/IndexedDB/sqlite/UniqueIDBDatabaseBackingStoreSQLite.cpp:
(WebKit::UniqueIDBDatabaseBackingStoreSQLite::createAndPopulateInitialMetadata): Add custom collation
  to the Records table.
(WebKit::UniqueIDBDatabaseBackingStoreSQLite::getOrEstablishMetadata): Install the custom collator.
(WebKit::UniqueIDBDatabaseBackingStoreSQLite::getKeyRecordFromObjectStore):
(WebKit::UniqueIDBDatabaseBackingStoreSQLite::getKeyRangeRecordFromObjectStore):
(WebKit::UniqueIDBDatabaseBackingStoreSQLite::collate): Collation function to be filled in later.
* DatabaseProcess/IndexedDB/sqlite/UniqueIDBDatabaseBackingStoreSQLite.h:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@162682 268f45cc-cd09-0410-ab3c-d52691b4dbfc