diff --git a/testing/embedder_test.cpp b/testing/embedder_test.cpp
index 6cbfbf5..fc6b4db 100644
--- a/testing/embedder_test.cpp
+++ b/testing/embedder_test.cpp
@@ -14,7 +14,6 @@
 #include <utility>
 #include <vector>
 
-#include "../fpdfsdk/include/fpdf_ext.h"
 #include "../fpdfsdk/include/fpdftext.h"
 #include "../fpdfsdk/include/fpdfview.h"
 #include "../core/include/fxcrt/fx_system.h"
@@ -94,54 +93,57 @@
 
 }  // namespace
 
-int Form_Alert(IPDF_JSPLATFORM*, FPDF_WIDESTRING, FPDF_WIDESTRING, int, int) {
-  printf("Form_Alert called.\n");
-  return 0;
-}
-
-void Unsupported_Handler(UNSUPPORT_INFO*, int type) {
-  std::string feature = "Unknown";
-  switch (type) {
-    case FPDF_UNSP_DOC_XFAFORM:
-      feature = "XFA";
-      break;
-    case FPDF_UNSP_DOC_PORTABLECOLLECTION:
-      feature = "Portfolios_Packages";
-      break;
-    case FPDF_UNSP_DOC_ATTACHMENT:
-    case FPDF_UNSP_ANNOT_ATTACHMENT:
-      feature = "Attachment";
-      break;
-    case FPDF_UNSP_DOC_SECURITY:
-      feature = "Rights_Management";
-      break;
-    case FPDF_UNSP_DOC_SHAREDREVIEW:
-      feature = "Shared_Review";
-      break;
-    case FPDF_UNSP_DOC_SHAREDFORM_ACROBAT:
-    case FPDF_UNSP_DOC_SHAREDFORM_FILESYSTEM:
-    case FPDF_UNSP_DOC_SHAREDFORM_EMAIL:
-      feature = "Shared_Form";
-      break;
-    case FPDF_UNSP_ANNOT_3DANNOT:
-      feature = "3D";
-      break;
-    case FPDF_UNSP_ANNOT_MOVIE:
-      feature = "Movie";
-      break;
-    case FPDF_UNSP_ANNOT_SOUND:
-      feature = "Sound";
-      break;
-    case FPDF_UNSP_ANNOT_SCREEN_MEDIA:
-    case FPDF_UNSP_ANNOT_SCREEN_RICHMEDIA:
-      feature = "Screen";
-      break;
-    case FPDF_UNSP_ANNOT_SIG:
-      feature = "Digital_Signature";
-      break;
+class EmbedderTestDefaultDelegate : public EmbedderTest::Delegate {
+ public:
+  int Alert(FPDF_WIDESTRING, FPDF_WIDESTRING, int, int) override {
+    printf("Form_Alert called.\n");
+    return 0;
   }
-  printf("Unsupported feature: %s.\n", feature.c_str());
-}
+
+  void UnsupportedHandler(int type) {
+    std::string feature = "Unknown";
+    switch (type) {
+      case FPDF_UNSP_DOC_XFAFORM:
+        feature = "XFA";
+        break;
+      case FPDF_UNSP_DOC_PORTABLECOLLECTION:
+        feature = "Portfolios_Packages";
+        break;
+      case FPDF_UNSP_DOC_ATTACHMENT:
+      case FPDF_UNSP_ANNOT_ATTACHMENT:
+        feature = "Attachment";
+        break;
+      case FPDF_UNSP_DOC_SECURITY:
+        feature = "Rights_Management";
+        break;
+      case FPDF_UNSP_DOC_SHAREDREVIEW:
+        feature = "Shared_Review";
+        break;
+      case FPDF_UNSP_DOC_SHAREDFORM_ACROBAT:
+      case FPDF_UNSP_DOC_SHAREDFORM_FILESYSTEM:
+      case FPDF_UNSP_DOC_SHAREDFORM_EMAIL:
+        feature = "Shared_Form";
+        break;
+      case FPDF_UNSP_ANNOT_3DANNOT:
+        feature = "3D";
+        break;
+      case FPDF_UNSP_ANNOT_MOVIE:
+        feature = "Movie";
+        break;
+      case FPDF_UNSP_ANNOT_SOUND:
+        feature = "Sound";
+        break;
+      case FPDF_UNSP_ANNOT_SCREEN_MEDIA:
+      case FPDF_UNSP_ANNOT_SCREEN_RICHMEDIA:
+        feature = "Screen";
+        break;
+      case FPDF_UNSP_ANNOT_SIG:
+        feature = "Digital_Signature";
+        break;
+    }
+    printf("Unsupported feature: %s.\n", feature.c_str());
+  }
+};
 
 class TestLoader {
  public:
@@ -170,6 +172,24 @@
 void Add_Segment(FX_DOWNLOADHINTS* pThis, size_t offset, size_t size) {
 }
 
+EmbedderTest::EmbedderTest() :
+      document_(nullptr),
+      form_handle_(nullptr),
+      avail_(nullptr),
+      loader_(nullptr),
+      file_length_(0),
+      file_contents_(nullptr) {
+  memset(&hints_, 0, sizeof(hints_));
+  memset(&file_access_, 0, sizeof(file_access_));
+  memset(&file_avail_, 0, sizeof(file_avail_));
+  default_delegate_ = new EmbedderTestDefaultDelegate();
+  delegate_ = default_delegate_;
+}
+
+EmbedderTest::~EmbedderTest() {
+  delete default_delegate_;
+}
+
 void EmbedderTest::SetUp() {
     v8::V8::InitializeICU();
 
@@ -182,11 +202,11 @@
 
     FPDF_InitLibrary();
 
-    UNSUPPORT_INFO unsuppored_info;
-    memset(&unsuppored_info, '\0', sizeof(unsuppored_info));
-    unsuppored_info.version = 1;
-    unsuppored_info.FSDK_UnSupport_Handler = Unsupported_Handler;
-    FSDK_SetUnSpObjProcessHandler(&unsuppored_info);
+    UNSUPPORT_INFO* info = static_cast<UNSUPPORT_INFO*>(this);
+    memset(info, 0, sizeof(UNSUPPORT_INFO));
+    info->version = 1;
+    info->FSDK_UnSupport_Handler = UnsupportedHandlerTrampoline;
+    FSDK_SetUnSpObjProcessHandler(info);
   }
 
 void EmbedderTest::TearDown() {
@@ -236,17 +256,17 @@
   (void) FPDF_GetDocPermissions(document_);
   (void) FPDFAvail_IsFormAvail(avail_, &hints_);
 
-  IPDF_JSPLATFORM platform_callbacks;
-  memset(&platform_callbacks, '\0', sizeof(platform_callbacks));
-  platform_callbacks.version = 1;
-  platform_callbacks.app_alert = Form_Alert;
+  IPDF_JSPLATFORM* platform = static_cast<IPDF_JSPLATFORM*>(this);
+  memset(platform, 0, sizeof(IPDF_JSPLATFORM));
+  platform->version = 1;
+  platform->app_alert = AlertTrampoline;
 
-  FPDF_FORMFILLINFO form_callbacks;
-  memset(&form_callbacks, '\0', sizeof(form_callbacks));
-  form_callbacks.version = 1;
-  form_callbacks.m_pJsPlatform = &platform_callbacks;
+  FPDF_FORMFILLINFO* formfillinfo = static_cast<FPDF_FORMFILLINFO*>(this);
+  memset(formfillinfo, 0, sizeof(FPDF_FORMFILLINFO));
+  formfillinfo->version = 1;
+  formfillinfo->m_pJsPlatform = platform;
 
-  form_handle_ = FPDFDOC_InitFormFillEnvironment(document_, &form_callbacks);
+  form_handle_ = FPDFDOC_InitFormFillEnvironment(document_, formfillinfo);
   FPDF_SetFormFieldHighlightColor(form_handle_, 0, 0xFFE4DD);
   FPDF_SetFormFieldHighlightAlpha(form_handle_, 100);
 
@@ -298,6 +318,23 @@
   FPDF_ClosePage(page);
 }
 
+// static
+void EmbedderTest::UnsupportedHandlerTrampoline(UNSUPPORT_INFO* info,
+                                                int type) {
+  EmbedderTest* test = static_cast<EmbedderTest*>(info);
+  test->delegate_->UnsupportedHandler(type);
+}
+
+// static
+int EmbedderTest::AlertTrampoline(IPDF_JSPLATFORM* platform,
+                                  FPDF_WIDESTRING message,
+                                  FPDF_WIDESTRING title,
+                                  int type,
+                                  int icon) {
+  EmbedderTest* test = static_cast<EmbedderTest*>(platform);
+  return test->delegate_->Alert(message, title, type, icon);
+}
+
 // Can't use gtest-provided main since we need to stash the path to the
 // executable in order to find the external V8 binary data files.
 int main(int argc, char** argv) {
diff --git a/testing/embedder_test.h b/testing/embedder_test.h
index 072dce3..ea93131 100644
--- a/testing/embedder_test.h
+++ b/testing/embedder_test.h
@@ -9,6 +9,7 @@
 
 #include "../core/include/fxcrt/fx_system.h"
 #include "../fpdfsdk/include/fpdf_dataavail.h"
+#include "../fpdfsdk/include/fpdf_ext.h"
 #include "../fpdfsdk/include/fpdfformfill.h"
 #include "../fpdfsdk/include/fpdfview.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -18,25 +19,35 @@
 
 // This class is used to load a PDF document, and then run programatic
 // API tests against it.
-class EmbedderTest : public ::testing::Test {
+class EmbedderTest : public ::testing::Test,
+                     public UNSUPPORT_INFO,
+                     public IPDF_JSPLATFORM,
+                     public FPDF_FORMFILLINFO {
  public:
-  EmbedderTest() :
-      document_(nullptr),
-      form_handle_(nullptr),
-      avail_(nullptr),
-      loader_(nullptr),
-      file_length_(0),
-      file_contents_(nullptr) {
-    memset(&hints_, 0, sizeof(hints_));
-    memset(&file_access_, 0, sizeof(file_access_));
-    memset(&file_avail_, 0, sizeof(file_avail_));
-  }
+  class Delegate {
+   public:
+    virtual ~Delegate() { }
 
-  virtual ~EmbedderTest() { }
+    // Equivalent to UNSUPPORT_INFO::FSDK_UnSupport_Handler().
+    virtual void UnsupportedHandler(int type) { }
+
+    // Equivalent to IPDF_JSPLATFORM::app_alert().
+    virtual int Alert(FPDF_WIDESTRING message, FPDF_WIDESTRING title,
+                      int type, int icon) {
+      return 0;
+    }
+  };
+
+  EmbedderTest();
+  virtual ~EmbedderTest();
 
   void SetUp() override;
   void TearDown() override;
 
+  void SetDelegate(Delegate* delegate) {
+    delegate_ = delegate ? delegate : default_delegate_;
+  }
+
   FPDF_DOCUMENT document() { return document_; }
   FPDF_FORMHANDLE form_handle() { return form_handle_; }
 
@@ -62,6 +73,8 @@
   virtual void UnloadPage(FPDF_PAGE page);
 
  protected:
+  Delegate* delegate_;
+  Delegate* default_delegate_;
   FPDF_DOCUMENT document_;
   FPDF_FORMHANDLE form_handle_;
   FPDF_AVAIL avail_;
@@ -73,6 +86,11 @@
   TestLoader* loader_;
   size_t file_length_;
   char* file_contents_;
+
+ private:
+  static void UnsupportedHandlerTrampoline(UNSUPPORT_INFO*, int type);
+  static int AlertTrampoline(IPDF_JSPLATFORM* plaform, FPDF_WIDESTRING message,
+                             FPDF_WIDESTRING title, int type, int icon);
 };
 
 #endif  // TESTING_EMBEDDER_TEST_H_