Implement FORM_GetFocusedText() API.

If there is a focused form field, get its text.

BUG=chromium:753216

Change-Id: I05294f14d05c1c86769055f6c9eaf9177787d9fd
Reviewed-on: https://pdfium-review.googlesource.com/12072
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>
diff --git a/fpdfsdk/cpdfsdk_annothandlermgr.cpp b/fpdfsdk/cpdfsdk_annothandlermgr.cpp
index e0405e8..52ab4dd 100644
--- a/fpdfsdk/cpdfsdk_annothandlermgr.cpp
+++ b/fpdfsdk/cpdfsdk_annothandlermgr.cpp
@@ -76,6 +76,10 @@
   GetAnnotHandler(pAnnot)->OnLoad(pAnnot);
 }
 
+WideString CPDFSDK_AnnotHandlerMgr::Annot_GetText(CPDFSDK_Annot* pAnnot) {
+  return GetAnnotHandler(pAnnot)->GetText(pAnnot);
+}
+
 WideString CPDFSDK_AnnotHandlerMgr::Annot_GetSelectedText(
     CPDFSDK_Annot* pAnnot) {
   return GetAnnotHandler(pAnnot)->GetSelectedText(pAnnot);