Add a null pointer check to CPDF_CalRGB::v_Load().

BUG=492055
R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1241923005 .
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
index 9e6ca67..101a197 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
@@ -348,6 +348,9 @@
 FX_BOOL CPDF_CalRGB::v_Load(CPDF_Document* pDoc, CPDF_Array* pArray)
 {
     CPDF_Dictionary* pDict = pArray->GetDict(1);
+    if (!pDict)
+        return FALSE;
+
     CPDF_Array* pParam = pDict->GetArray(FX_BSTRC("WhitePoint"));
     int i;
     for (i = 0; i < 3; i ++) {