Define behaviors of FPDF_RenderPageBitmap_Retail and FPDF_FFLDraw.

Previously, PDFium only supported widget annotations to draw forms. As
we've implemented other annotations, the behavior of
FPDF_RenderPageBitmap_Retail and FPDF_FFLDraw changed. So, this CL
clearly defines what needs to be done in FPDF_RenderPageBitmap_Retail
and FPDF_FFLDraw.

This CL first assumes that PDFium users will always call
FPDF_RenderPageBitmap_Retail and FPDF_FFLDraw to render PDF pages,
because otherwise they are not able to support PDF forms.

FPDF_RenderPageBitmap_Retail should only deal with non-widget
annotations, such as highlight, underline, text, etc. If
FPDF_ANNOT flag is passed, non-widget annotations are drawn. Otherwise,
they are hidden.

FPDF_FFLDraw should only deal with annotations that requires
user-interaction, such as widget annotations and popup annotation. Since
popup annotation is associated with non-widget annotation, they should
not be drawn if the associated annotation is hidden. Thus, if FPDF_ANNOT
flag is passed, popup annotations are drawn. Otherwise, they are hidden.
Widget annotations should be always drawn regardless of FPDF_ANNOT flag
since they need to be always displayed for PDF forms.

Also, roll DEPS for testing/corpus to 8485b30.

BUG=pdfium:594

Review-Url: https://codereview.chromium.org/2323203002
diff --git a/fpdfsdk/cpdfsdk_annothandlermgr.cpp b/fpdfsdk/cpdfsdk_annothandlermgr.cpp
index 12362e3..0fd48d2 100644
--- a/fpdfsdk/cpdfsdk_annothandlermgr.cpp
+++ b/fpdfsdk/cpdfsdk_annothandlermgr.cpp
@@ -93,9 +93,11 @@
 void CPDFSDK_AnnotHandlerMgr::Annot_OnDraw(CPDFSDK_PageView* pPageView,
                                            CPDFSDK_Annot* pAnnot,
                                            CFX_RenderDevice* pDevice,
-                                           CFX_Matrix* pUser2Device) {
+                                           CFX_Matrix* pUser2Device,
+                                           bool bDrawAnnots) {
   ASSERT(pAnnot);
-  GetAnnotHandler(pAnnot)->OnDraw(pPageView, pAnnot, pDevice, pUser2Device);
+  GetAnnotHandler(pAnnot)->OnDraw(pPageView, pAnnot, pDevice, pUser2Device,
+                                  bDrawAnnots);
 }
 
 FX_BOOL CPDFSDK_AnnotHandlerMgr::Annot_OnLButtonDown(