Fix memory leak in fxge.SkiaState tests.

In Harness(), CFX_DIBitmap::Create() allocates memory for |bitmap| but
the memory never gets freed at the end of the function. Use
ScopedFPDFBitmap to automatically destroy |bitmap| when Harness()
finishes to avoid the memory leak.

Bug: pdfium:1378
Change-Id: I84e87238734a05c1a711a3889b48f01cb5751ee2
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/59310
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>

core/fxge/skia/fx_skia_device_embeddertest.cpp

diff --git a/core/fxge/skia/fx_skia_device_embeddertest.cpp b/core/fxge/skia/fx_skia_device_embeddertest.cpp
index 588cb96..48734ee 100644
--- a/core/fxge/skia/fx_skia_device_embeddertest.cpp
+++ b/core/fxge/skia/fx_skia_device_embeddertest.cpp
@@ -10,6 +10,7 @@
 #include "core/fxge/skia/fx_skia_device.h"
 #include "core/fxge/text_char_pos.h"
 #include "fpdfsdk/cpdfsdk_helpers.h"
+#include "public/cpp/fpdf_scopers.h"
 #include "public/fpdfview.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/skia/include/core/SkPictureRecorder.h"
@@ -120,13 +121,13 @@
              const State& state) {
   int h = 1;
   int w = 4;
-  FPDF_BITMAP bitmap = FPDFBitmap_Create(w, h, 1);
+  ScopedFPDFBitmap bitmap(FPDFBitmap_Create(w, h, 1));
   EXPECT_NE(nullptr, bitmap);
   if (!bitmap)
     return;
-  FPDFBitmap_FillRect(bitmap, 0, 0, w, h, 0x00000000);
+  FPDFBitmap_FillRect(bitmap.get(), 0, 0, w, h, 0x00000000);
   CFX_DefaultRenderDevice geDevice;
-  RetainPtr<CFX_DIBitmap> pBitmap(CFXDIBitmapFromFPDFBitmap(bitmap));
+  RetainPtr<CFX_DIBitmap> pBitmap(CFXDIBitmapFromFPDFBitmap(bitmap.get()));
   geDevice.Attach(pBitmap, false, nullptr, false);
   CFX_SkiaDeviceDriver* driver =
       static_cast<CFX_SkiaDeviceDriver*>(geDevice.GetDeviceDriver());