Use Drive v2 API: enable behind --enable-drive-api flag

chrome/browser/chromeos/gdata/gdata_documents_service.h

Index: chrome/browser/chromeos/gdata/gdata_documents_service.h
diff --git a/chrome/browser/chromeos/gdata/gdata_documents_service.h b/chrome/browser/chromeos/gdata/gdata_documents_service.h
index aae3f0755f34dec9c400de221ba8b235907d877f..129410197b8e40bcffd1342a434a9ef502bc24e2 100644
--- a/chrome/browser/chromeos/gdata/gdata_documents_service.h
+++ b/chrome/browser/chromeos/gdata/gdata_documents_service.h
@@ -82,7 +82,7 @@ class DocumentsServiceInterface {
   virtual ~DocumentsServiceInterface() {}
 
   // Initializes the documents service tied with |profile|.
-  virtual void Initialize(Profile* profile) = 0;
+  virtual void Initialize(Profile* profile, bool use_drive_api) = 0;
 
   // Retrieves the operation registry.
   virtual GDataOperationRegistry* operation_registry() const = 0;
@@ -207,7 +207,7 @@ class DocumentsService : public DocumentsServiceInterface {
   GDataAuthService* auth_service_for_testing();
 
   // DocumentsServiceInterface Overrides
-  virtual void Initialize(Profile* profile) OVERRIDE;
+  virtual void Initialize(Profile* profile, bool use_drive_api) OVERRIDE;
   virtual GDataOperationRegistry* operation_registry() const OVERRIDE;
   virtual void CancelAll() OVERRIDE;
   virtual void Authenticate(const AuthStatusCallback& callback) OVERRIDE;
@@ -262,6 +262,9 @@ class DocumentsService : public DocumentsServiceInterface {
 
   scoped_ptr<GDataOperationRunner> runner_;
 
+  // If true use Drive v2 API instead of Document List API.
+  bool use_drive_api_;
+
   DISALLOW_COPY_AND_ASSIGN(DocumentsService);
 };