Use floats in experimental APIs.

Floats work more seamlessly with the underlying implementation, which
uses floats instead of doubles. Along the way, take advantage of
FS_MATRIX to reduce the number of parameters in these APIs. Also
introduce FS_POINTF for the same purpose.

NOTE: This breaks API compatibility.

The modified APIS are:
- FPDFAnnot_GetFormFieldAtPoint
- FPDFFormObj_GetMatrix
- FPDFPath_GetMatrix
- FPDFPath_SetMatrix
- FPDFText_GetCharAngle
- FPDFText_GetLooseCharBox
- FPDFTextObj_GetFontSize
- FPDFTextObj_GetMatrix

Bug: pdfium:996
Change-Id: I58d43928811cf019fef3017ebce670322720db4d
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/61873
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
diff --git a/fpdfsdk/fpdf_doc.cpp b/fpdfsdk/fpdf_doc.cpp
index b789891..ec361d5 100644
--- a/fpdfsdk/fpdf_doc.cpp
+++ b/fpdfsdk/fpdf_doc.cpp
@@ -367,7 +367,7 @@
     return false;
 
   CPDF_Dictionary* pAnnotDict = CPDFDictionaryFromFPDFLink(link_annot);
-  *rect = FSRECTFFromCFXFloatRect(pAnnotDict->GetRectFor("Rect"));
+  *rect = FSRectFFromCFXFloatRect(pAnnotDict->GetRectFor("Rect"));
   return true;
 }