Fix four annoying warnings:

core/src/fpdfapi/fpdf_edit/fpdf_edit_image.cpp

Index: core/src/fpdfapi/fpdf_edit/fpdf_edit_image.cpp
diff --git a/core/src/fpdfapi/fpdf_edit/fpdf_edit_image.cpp b/core/src/fpdfapi/fpdf_edit/fpdf_edit_image.cpp
index a5a91ebc53ba719e09d0a6705c601a5aa9acfced..9096bf938e8d49591bb0a234b3f7ee1439746287 100644
--- a/core/src/fpdfapi/fpdf_edit/fpdf_edit_image.cpp
+++ b/core/src/fpdfapi/fpdf_edit/fpdf_edit_image.cpp
@@ -190,8 +190,10 @@ void CPDF_Image::SetImage(const CFX_DIBitmap* pBitmap, FX_INT32 iCompress, IFX_F
         }
     }
     const CFX_DIBitmap* pMaskBitmap = NULL;
+    FX_BOOL bDeleteMask = FALSE;
     if (pBitmap->HasAlpha()) {
         pMaskBitmap = pBitmap->GetAlphaMask();
+        bDeleteMask = TRUE;
     }
     if (!pMaskBitmap && pMask) {
         FXDIB_Format maskFormat = pMask->GetFormat();
@@ -204,7 +206,6 @@ void CPDF_Image::SetImage(const CFX_DIBitmap* pBitmap, FX_INT32 iCompress, IFX_F
         FX_INT32 maskHeight = pMaskBitmap->GetHeight();
         FX_LPBYTE mask_buf = NULL;
         FX_STRSIZE mask_size;
-        FX_BOOL bDeleteMask = TRUE;
         CPDF_Dictionary* pMaskDict = new CPDF_Dictionary;
         pMaskDict->SetAtName(FX_BSTRC("Type"), FX_BSTRC("XObject"));
         pMaskDict->SetAtName(FX_BSTRC("Subtype"), FX_BSTRC("Image"));
@@ -223,24 +224,20 @@ void CPDF_Image::SetImage(const CFX_DIBitmap* pBitmap, FX_INT32 iCompress, IFX_F
                 FXSYS_memcpy32(mask_buf + a * maskWidth, pMaskBitmap->GetScanline(a), maskWidth);
             }
         }
-        if (pMaskDict) {
-            pMaskDict->SetAtInteger(FX_BSTRC("Length"), mask_size);
-            CPDF_Stream* pMaskStream = NULL;
-            if (bUseMatte) {
-                int a, r, g, b;
-                ArgbDecode(*(pParam->pMatteColor), a, r, g, b);
-                CPDF_Array* pMatte = new CPDF_Array;
-                pMatte->AddInteger(r);
-                pMatte->AddInteger(g);
-                pMatte->AddInteger(b);
-                pMaskDict->SetAt(FX_BSTRC("Matte"), pMatte);
-            }
-            pMaskStream = new CPDF_Stream(mask_buf, mask_size, pMaskDict);
-            m_pDocument->AddIndirectObject(pMaskStream);
-            bDeleteMask = FALSE;
-            pDict->SetAtReference(FX_BSTRC("SMask"), m_pDocument, pMaskStream);
+        pMaskDict->SetAtInteger(FX_BSTRC("Length"), mask_size);
+        if (bUseMatte) {
+            int a, r, g, b;
+            ArgbDecode(*(pParam->pMatteColor), a, r, g, b);
+            CPDF_Array* pMatte = new CPDF_Array;
+            pMatte->AddInteger(r);
+            pMatte->AddInteger(g);
+            pMatte->AddInteger(b);
+            pMaskDict->SetAt(FX_BSTRC("Matte"), pMatte);
         }
-        if (pBitmap->HasAlpha()) {
+        CPDF_Stream* pMaskStream = new CPDF_Stream(mask_buf, mask_size, pMaskDict);
+        m_pDocument->AddIndirectObject(pMaskStream);
+        pDict->SetAtReference(FX_BSTRC("SMask"), m_pDocument, pMaskStream);
+        if (bDeleteMask) {
             delete pMaskBitmap;
         }
     }