Zero-fill PatternValue::m_Comps

Unlike std::vector<> upon resizing, std::array<> doesn't
zero-initialize its members, so we need to do this explicitly.

Bug: chromium:982768
Change-Id: I9f2a5bb76ecd5c2c1ecbf74d23052f73b88c2562
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/57570
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>

core/fpdfapi/page/cpdf_colorspace.cpp

diff --git a/core/fpdfapi/page/cpdf_colorspace.cpp b/core/fpdfapi/page/cpdf_colorspace.cpp
index 9e1dab4..3f88149 100644
--- a/core/fpdfapi/page/cpdf_colorspace.cpp
+++ b/core/fpdfapi/page/cpdf_colorspace.cpp
@@ -442,7 +442,9 @@
 
 }  // namespace
 
-PatternValue::PatternValue() = default;
+PatternValue::PatternValue() {
+  std::fill(std::begin(m_Comps), std::end(m_Comps), 0.0f);
+}
 
 PatternValue::PatternValue(const PatternValue& that) = default;