[Windows][tts_platform_fuzzer] Call CoInitiliazeEx once before fuzzing

Call CoInitiliazeEx once before fuzzing so that CoCreateInstance
succeeds.

Change-Id: I6e6c1fed60da7967a2294b3d781c2d1bd468bbbb
Bug: 904877
Reviewed-on: https://chromium-review.googlesource.com/c/1342620Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Jonathan Metzman <metzman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609873}

chrome/browser/speech/tts_platform_fuzzer.cc

@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <objbase.h>
+
+#include "build/build_config.h"
 #include "chrome/browser/speech/tts_platform.h"
 
 // Entry point for LibFuzzer.
@@ -15,6 +18,14 @@ extern "C" int LLVMFuzzerTestOneInput(const unsigned char* data, size_t size) {
   params.rate = 1.0;
   params.volume = 0.1;
 
+#if defined(OS_WIN)
+  static bool initialized = false;
+  if (!initialized) {
+    initialized = true;
+    CoInitializeEx(nullptr, COINIT_APARTMENTTHREADED);
+  }
+#endif
+
   // First byte gives us the utterance ID.
   size_t i = 0;
   if (i < size)