Forward declare CommandLine and NoDestructor in quic_flags_impl.h.

These are not commonly included in header files, but fairly often used
in cc files, so including them in a widely used header can lead to
IWYU issues (this header isn't widely used directly, but was
transitively included in 8,000+ files).

Bug: None
Change-Id: Id08418b088d6b9e55cd9c86852363b016b842b18
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2300033Reviewed-by: Zhongyi Shi <zhongyi@chromium.org>
Commit-Queue: Matt Menke <mmenke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#789703}

net/quic/platform/impl/quic_flags_impl.h

@@ -11,9 +11,7 @@
 #include <string>
 #include <vector>
 
-#include "base/command_line.h"
 #include "base/export_template.h"
-#include "base/no_destructor.h"
 #include "base/optional.h"
 #include "net/third_party/quiche/src/common/platform/api/quiche_string_piece.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_export.h"
@@ -22,6 +20,12 @@
 #include "net/quic/quic_flags_list.h"
 #undef QUIC_FLAG
 
+namespace base {
+class CommandLine;
+template <typename T>
+class NoDestructor;
+}  // namespace base
+
 // API compatibility with new-style flags.
 
 inline bool GetQuicFlagImpl(bool flag) {

net/quic/platform/impl/quic_flags_test.cc

@@ -4,6 +4,7 @@
 
 #include "net/third_party/quiche/src/quic/platform/api/quic_flags.h"
 
+#include "base/command_line.h"
 #include "base/optional.h"
 #include "base/stl_util.h"
 #include "base/strings/strcat.h"

services/network/trust_tokens/trust_token_request_issuance_helper_unittest.cc

@@ -7,6 +7,7 @@
 #include <memory>
 
 #include "base/callback.h"
+#include "base/no_destructor.h"
 #include "base/test/task_environment.h"
 #include "net/base/load_flags.h"
 #include "net/base/request_priority.h"

services/network/trust_tokens/trust_token_request_redemption_helper_unittest.cc

@@ -7,6 +7,7 @@
 #include <memory>
 
 #include "base/callback.h"
+#include "base/no_destructor.h"
 #include "base/test/task_environment.h"
 #include "net/base/load_flags.h"
 #include "net/base/request_priority.h"

services/network/websocket.cc

@@ -11,6 +11,7 @@
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
+#include "base/command_line.h"
 #include "base/feature_list.h"
 #include "base/location.h"
 #include "base/logging.h"