Sort include entries.

This CL updates all of the includes to be correctly sorted. A PRESUBMIT warning
is added (from chromium) that will warn if the includes are in the wrong order on upload.

Review-Url: https://codereview.chromium.org/2337293002
diff --git a/fpdfsdk/cpdfsdk_annothandlermgr.cpp b/fpdfsdk/cpdfsdk_annothandlermgr.cpp
index 8fa1093..1f88e16 100644
--- a/fpdfsdk/cpdfsdk_annothandlermgr.cpp
+++ b/fpdfsdk/cpdfsdk_annothandlermgr.cpp
@@ -18,8 +18,8 @@
 #include "fpdfsdk/include/cpdfsdk_widgethandler.h"
 
 #ifdef PDF_ENABLE_XFA
-#include "fpdfsdk/include/cpdfsdk_xfawidgethandler.h"
 #include "fpdfsdk/fpdfxfa/include/fpdfxfa_page.h"
+#include "fpdfsdk/include/cpdfsdk_xfawidgethandler.h"
 #include "xfa/fxfa/include/xfa_ffpageview.h"
 #include "xfa/fxfa/include/xfa_ffwidget.h"
 #endif  // PDF_ENABLE_XFA