Fix threading issues in aw form database

android_webview/browser/aw_browser_context.h

Index: android_webview/browser/aw_browser_context.h
diff --git a/android_webview/browser/aw_browser_context.h b/android_webview/browser/aw_browser_context.h
index 1654d9a86753f5876db98134315744a43c3fccc0..fbc82a9124c607f32e07e784e2cea69f3eb1b3bd 100644
--- a/android_webview/browser/aw_browser_context.h
+++ b/android_webview/browser/aw_browser_context.h
@@ -13,6 +13,8 @@
 #include "base/files/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/synchronization/lock.h"
+#include "base/synchronization/waitable_event.h"
 #include "components/visitedlink/browser/visitedlink_delegate.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/content_browser_client.h"
@@ -104,6 +106,8 @@ class AwBrowserContext : public content::BrowserContext,
       const scoped_refptr<URLEnumerator>& enumerator) OVERRIDE;
 
  private:
+  void CreateFormDatabaseServiceOnUiThread();
+
   // The file path where data for this context is persisted.
   base::FilePath context_storage_path_;
 
@@ -122,6 +126,9 @@ class AwBrowserContext : public content::BrowserContext,
 
   bool user_pref_service_ready_;
 
+  base::WaitableEvent form_database_service_creation_;
+  base::Lock form_database_lock_;
+
   DISALLOW_COPY_AND_ASSIGN(AwBrowserContext);
 };