Fix uninitialized nresults in GetRGB

BUG=387809
R=palmer@chromium.org

Review URL: https://codereview.chromium.org/379283003
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
index b661bbe..408a553 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
@@ -945,7 +945,7 @@
         return TRUE;
     }
     CFX_FixedBufGrow<FX_FLOAT, 16> results(m_pFunc->CountOutputs());
-    int nresults;
+    int nresults = 0;
     m_pFunc->Call(pBuf, 1, results, nresults);
     if (nresults == 0) {
         return FALSE;