Bug 1764725 - Fix gtest uninitialized warnings with GCC. r=nika

Differential Revision: https://phabricator.services.mozilla.com/D144076

third_party/googletest/googletest/include/gtest/gtest-matchers.h

@@ -299,17 +299,18 @@ class MatcherBase : private MatcherDescriberInterface {
   }
 
  protected:
-  MatcherBase() : vtable_(nullptr) {}
+  MatcherBase() : vtable_(nullptr), buffer_() {}
 
   // Constructs a matcher from its implementation.
   template <typename U>
-  explicit MatcherBase(const MatcherInterface<U>* impl) {
+  explicit MatcherBase(const MatcherInterface<U>* impl)
+      : vtable_(nullptr), buffer_() {
     Init(impl);
   }
 
   template <typename M, typename = typename std::remove_reference<
                             M>::type::is_gtest_matcher>
-  MatcherBase(M&& m) {  // NOLINT
+  MatcherBase(M&& m) : vtable_(nullptr), buffer_() {  // NOLINT
     Init(std::forward<M>(m));
   }
 

third_party/googletest/issue3514.patch

@@ -0,0 +1,26 @@
+diff --git a/googletest/include/gtest/gtest-matchers.h b/googletest/include/gtest/gtest-matchers.h
+index 75836605..3d3bea31 100644
+--- a/googletest/include/gtest/gtest-matchers.h
++++ b/googletest/include/gtest/gtest-matchers.h
+@@ -299,17 +299,18 @@ class MatcherBase : private MatcherDescriberInterface {
+   }
+ 
+  protected:
+-  MatcherBase() : vtable_(nullptr) {}
++  MatcherBase() : vtable_(nullptr), buffer_() {}
+ 
+   // Constructs a matcher from its implementation.
+   template <typename U>
+-  explicit MatcherBase(const MatcherInterface<U>* impl) {
++  explicit MatcherBase(const MatcherInterface<U>* impl)
++      : vtable_(nullptr), buffer_() {
+     Init(impl);
+   }
+ 
+   template <typename M, typename = typename std::remove_reference<
+                             M>::type::is_gtest_matcher>
+-  MatcherBase(M&& m) {  // NOLINT
++  MatcherBase(M&& m) : vtable_(nullptr), buffer_() {  // NOLINT
+     Init(std::forward<M>(m));
+   }
+