Consistently pass FPDF handles by value.

Change-Id: I1b31217c756620873f59527768464aec02a82900
Reviewed-on: https://pdfium-review.googlesource.com/6677
Commit-Queue: dsinclair <dsinclair@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>
diff --git a/samples/pdfium_test.cc b/samples/pdfium_test.cc
index 5520fa4..86f6f89 100644
--- a/samples/pdfium_test.cc
+++ b/samples/pdfium_test.cc
@@ -755,8 +755,8 @@
 
 void Add_Segment(FX_DOWNLOADHINTS* hints, size_t offset, size_t size) {}
 
-void SendPageEvents(const FPDF_FORMHANDLE& form,
-                    const FPDF_PAGE& page,
+void SendPageEvents(FPDF_FORMHANDLE form,
+                    FPDF_PAGE page,
                     const std::string& events) {
   auto lines = StringSplit(events, '\n');
   for (auto line : lines) {
diff --git a/testing/test_support.h b/testing/test_support.h
index a2d3528..7795be4 100644
--- a/testing/test_support.h
+++ b/testing/test_support.h
@@ -70,7 +70,7 @@
 
 // Converts a FPDF_WIDESTRING to a std::wstring.
 // Deals with differences between UTF16LE and wchar_t.
-std::wstring GetPlatformWString(const FPDF_WIDESTRING wstr);
+std::wstring GetPlatformWString(FPDF_WIDESTRING wstr);
 
 // Returns a newly allocated FPDF_WIDESTRING.
 // Deals with differences between UTF16LE and wchar_t.