Simplify some FPDF edit functions.

Fix an unlikely memory leak in FPDFPage_InsertObject().

BUG=pdfium:545

Review-Url: https://codereview.chromium.org/2195643002
diff --git a/fpdfsdk/fpdfeditimg.cpp b/fpdfsdk/fpdfeditimg.cpp
index 4429dcd..b2c2577 100644
--- a/fpdfsdk/fpdfeditimg.cpp
+++ b/fpdfsdk/fpdfeditimg.cpp
@@ -17,9 +17,9 @@
   CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
   if (!pDoc)
     return nullptr;
+
   CPDF_ImageObject* pImageObj = new CPDF_ImageObject;
-  CPDF_Image* pImg = new CPDF_Image(pDoc);
-  pImageObj->m_pImage = pImg;
+  pImageObj->m_pImage = new CPDF_Image(pDoc);
   return pImageObj;
 }
 
@@ -32,13 +32,12 @@
     return FALSE;
 
   IFX_FileRead* pFile = new CPDF_CustomAccess(fileAccess);
-  CPDF_ImageObject* pImgObj = (CPDF_ImageObject*)image_object;
+  CPDF_ImageObject* pImgObj = reinterpret_cast<CPDF_ImageObject*>(image_object);
   pImgObj->m_GeneralState.GetModify();
   for (int index = 0; index < nCount; index++) {
     CPDF_Page* pPage = CPDFPageFromFPDFPage(pages[index]);
-    if (!pPage)
-      continue;
-    pImgObj->m_pImage->ResetCache(pPage, nullptr);
+    if (pPage)
+      pImgObj->m_pImage->ResetCache(pPage, nullptr);
   }
   pImgObj->m_pImage->SetJpegImage(pFile);
 
@@ -54,13 +53,14 @@
                                                    double f) {
   if (!image_object)
     return FALSE;
-  CPDF_ImageObject* pImgObj = (CPDF_ImageObject*)image_object;
-  pImgObj->m_Matrix.a = (FX_FLOAT)a;
-  pImgObj->m_Matrix.b = (FX_FLOAT)b;
-  pImgObj->m_Matrix.c = (FX_FLOAT)c;
-  pImgObj->m_Matrix.d = (FX_FLOAT)d;
-  pImgObj->m_Matrix.e = (FX_FLOAT)e;
-  pImgObj->m_Matrix.f = (FX_FLOAT)f;
+
+  CPDF_ImageObject* pImgObj = reinterpret_cast<CPDF_ImageObject*>(image_object);
+  pImgObj->m_Matrix.a = static_cast<FX_FLOAT>(a);
+  pImgObj->m_Matrix.b = static_cast<FX_FLOAT>(b);
+  pImgObj->m_Matrix.c = static_cast<FX_FLOAT>(c);
+  pImgObj->m_Matrix.d = static_cast<FX_FLOAT>(d);
+  pImgObj->m_Matrix.e = static_cast<FX_FLOAT>(e);
+  pImgObj->m_Matrix.f = static_cast<FX_FLOAT>(f);
   pImgObj->CalcBoundingBox();
   return TRUE;
 }
@@ -71,17 +71,15 @@
                                                    FPDF_BITMAP bitmap) {
   if (!image_object || !bitmap || !pages)
     return FALSE;
-  CFX_DIBitmap* pBmp = nullptr;
-  pBmp = (CFX_DIBitmap*)bitmap;
-  CPDF_ImageObject* pImgObj = (CPDF_ImageObject*)image_object;
+
+  CPDF_ImageObject* pImgObj = reinterpret_cast<CPDF_ImageObject*>(image_object);
   pImgObj->m_GeneralState.GetModify();
   for (int index = 0; index < nCount; index++) {
     CPDF_Page* pPage = CPDFPageFromFPDFPage(pages[index]);
-    if (!pPage)
-      continue;
-    pImgObj->m_pImage->ResetCache(pPage, nullptr);
+    if (pPage)
+      pImgObj->m_pImage->ResetCache(pPage, nullptr);
   }
-  pImgObj->m_pImage->SetImage(pBmp, FALSE);
+  pImgObj->m_pImage->SetImage(reinterpret_cast<CFX_DIBitmap*>(bitmap), FALSE);
   pImgObj->CalcBoundingBox();
   return TRUE;
 }